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To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany a
a
b
Beenish Nafees , Andrew Lloyd , Eric Elkin & Terri Porret
c
a a
ICON plc, Oxford, UK
b b
ICON plc, San Francisco, USA
c c
Coloplast UK Ltd, Peterborough, UK Published online: 02 Jul 2015.
Click for updates To cite this article: Beenish Nafees, Andrew Lloyd, Eric Elkin & Terri Porret (2015) To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany, Current Medical Research and Opinion, 31:4, 687-695 To link to this article: http://dx.doi.org/10.1185/03007995.2015.1008688
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Current Medical Research & Opinion 0300-7995 doi:10.1185/03007995.2015.1008688
Vol. 31, No. 4, 2015, 687–695
Article ST-0350.R1/1008688 All rights reserved: reproduction in whole or part not permitted
Current Medical Research and Opinion 2015.31:687-695.
Original article To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany
Beenish Nafees Andrew Lloyd ICON plc, Oxford, UK
Eric Elkin
Abstract Objectives: To explore patient preferences regarding stoma appliances in the UK, France and Germany and to estimate willingness to pay (WTP) for attributes of stoma appliances.
ICON plc, San Francisco, USA
Terri Porret Coloplast UK Ltd, Peterborough, UK Address for correspondence: Beenish Nafees, Senior Outcomes Researcher, Seacourt Tower, West Way, Oxford OX2 0JJ, UK. Tel.: +44 (0)7957 634170; [email protected] Keywords: Discrete choice experiment – Preference – Stoma care Accepted: 13 January 2015; published online: 2 March 2015 Citation: Curr Med Res Opin 2015; 31:687–95
Research design and methods: A discrete choice (DCE) survey was developed based on published literature, attributes of current available appliances and qualitative interviews with patients from the UK (N ¼ 3), France (N ¼ 2) and Germany (N ¼ 2). Members from a patient panel in the UK, France and Germany were asked to participate in the DCE survey and to fill out two quality of life (QoL) questionnaires. Data were analyzed using the conditional logit model whereby the coefficients obtained from the model provided an estimate of the (log) odds ratios (ORs) of preference for attributes. WTP was estimated for each level of a given identified attribute. Results: Seven key attributes were identified for the DCE survey: comfort and elastic flexibility, skin problems, early detection of leakage, leakage, filter performance, service/help after hospital discharge and out-of-pocket cost. A total of 415 participants (166 patients in UK, 99 in France, and 150 in Germany) completed the questionnaires. All attributes were significant predictors of choice. The two most important drivers of preference were the attributes comfort and elastic flexibility and skin problems which resulted in high WTP values. Appliances which were able to detect episodes of leakage were also of high importance to participants’ appliances. Conclusions: The results show the importance of different attributes of stoma appliances for patients. Improving comfort and elastic flexibility, and risk of skin problems were the most important aspects of appliances. The WTP values indicate the value people place on improvement in each attribute of appliances.
Introduction A stoma is a surgically created opening connecting an internal organ to the surface of the body where waste matter can be collected using an ostomy appliance. Living with a stoma is life-changing, where complications such as leakage, skin irritation and loss of bodily function may negatively affect physical wellbeing and health related quality of life (HRQL)1,2. New innovations in stoma care are therefore of great importance for people with a stoma and even small improvements in the functionality or performance of an appliance have been shown to produce important gains in HRQL3. Most ostomy pouching systems are designed to collect stoma output, be odor-free and ! 2015 Informa UK Ltd www.cmrojournal.com
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skin-friendly4. Skin irritation from the use of ostomy devices is an important concern for patients and may affect decisions regarding the choice of devices3,5. Pittman et al. explored how ostomy complications (such as skin irritation, leakage, and difficulty adjusting to an ostomy) affect people’s HRQL through research with 239 US veterans3. Participants completed the City of Hope Quality of Life: Ostomy Instrument (mCOHQOL-Ostomy). Having an ileostomy was associated with higher severity of skin irritation than having a colostomy. The research highlighted the importance of effective communication with patients. Patients who had received education before surgery were significantly less likely to report problems with skin irritation and leakage (p50.01). The research also demonstrated that overall HRQL was predicted by the severity of skin irritation, leakage and difficulty adjusting to the ostomy device. The research from Pittman and others shows the potential for understanding the benefit or value of improvements in ostomy product design by measuring patients’ HRQL1–3. An alternative approach to the assessment of the benefit of new ostomy devices is through the use of patient preference surveys which specifically estimate how much value users place on different aspects of the design. One methodology that has been quite widely used to do this is the discrete choice experiment (DCE), which is a stated preference survey method. A DCE can capture participants’ strength of preference for the characteristics or attributes of a product and can help identify the relative importance of different attributes. We can also understand the degree to which people are willing to trade between the attributes (estimated using marginal rates of substitution). In a DCE study strength of preference can be estimated using willingness to pay (WTP). WTP can be estimated by including out-of-pocket cost as an attribute in the survey and then exploring the extent to which people are willing to trade total cost against improvements in features or design. The aim of the current study was to elicit patient preferences regarding stoma appliances amongst participants in the UK, France and Germany and to estimate willingness to pay for attributes of stoma appliances.
Patients and methods Identification of attributes A literature review, interviews with clinical experts and patients, and a review of characteristics of currently available appliances were undertaken to help identify the important aspects or attributes of stoma care appliances for inclusion in the survey. The literature search was carried out in PubMed, EMBASE and Google Scholar (2001– 2014, in English) and was designed to identify evidence 688
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regarding common and important aspects of stoma appliances such as impact on skin condition, and the risk of leakage. The search strategy identified 10 relevant articles regarding patient HRQL and preferences regarding ostomy devices. Seven preliminary attributes were selected for further examination: comfort and flexibility, skin problems, early detection of leakage, leakage risk, filter life-time, service/help after hospital discharge, and out-of-pocket cost (included to estimate willingness to pay). Levels for each attribute were determined based on the literature search and interviews.
Development of DCE survey A preliminary version of the survey was developed based on these attributes. In the survey, the participants were presented with pairs of hypothetical appliances. An orthogonal fractional factorial design based on a published array was used to specify the combinations of attributes and levels in each choice6. A fold-over design was used to produce the pairs of choices. The pairs present two hypothetical appliances (appliance A or appliance B) and participants were requested to select their preferred appliance and whether they would prefer the hypothetical appliance over the current appliance. The survey consisted of 18 pairs of choice sets and included a consistency check. The survey also collected background socio-demographic information. The survey was translated for use in each country and cost levels were adapted between countries using the purchasing power parity estimates7. Semi-structured interviews with stoma patients from the UK (N ¼ 3), France (N ¼ 2) and Germany (N ¼ 2) were performed to explore their interpretation and understanding of the survey. The participants were asked to discuss each attribute, how it impacts their daily life, their current appliance and their preferences regarding aspects of appliances. They were also asked to suggest improvements and modifications to the survey. Interview data were analyzed and attributes and levels were finalized on the basis of these interviews. The final attributes and selected levels are presented in Table 1. The out-of-pocket cost attribute was described as a hypothetical cost and was described as ‘This treatment feature relates to how much more a monthly supply of appliances may cost you over and above your original monthly health insurance payment. Although you may not pay anything for your current appliance, it is possible that you may be willing to pay more for a monthly supply of improved appliances’. An electronic version of the survey was developed for administration via the web. Attention was paid to address online usability concerns in this process, e.g. ease of navigation online, moving back and forth in the survey, and comprehensiveness. www.cmrojournal.com ! 2015 Informa UK Ltd
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Table 1. Ostomy device attributes and levels with details regarding how the attribute was described. Attribute
Level
Comfort and elastic flexibility This feature relates to the elastic flexibility of the adhesive material that affects the fit between the appliance and your body, and how ‘comfortable’ it is in terms of fit. For this feature, please imagine that you have no soreness or redness around your stoma. Later on in the survey, we will present you with new appliances which will vary in terms of comfort and elastic flexibility. Generally, if the adhesive material has elastic flexibility, it will be better at following the movements of the skin and therefore will be more comfortable. Skin problems People can experience skin problems around the stoma due to problems with various ostomy appliances like leakages leading to faecal matter or urine on the skin. The skin problems may include itchiness, redness, allergic reactions, cuts or stripping of the skin and may lead to you seeking advice from your stoma care nurse.
The device has elastic flexibility, follows natural movements of the skin and is comfortable The device has very little elastic flexibility, the skin partly follows the movements of the device and is a little uncomfortable The device has no elastic flexibility, the skin follows the movements of the device and is always uncomfortable
Early detection of leakage This appliance feature relates to an ostomy appliance which may be able to provide a warning to detect early signs of leakage. This feature would be built into the appliance and would be able to detect all or some episodes of leakage. If it is able to detect leakage, this feature would allow people to feel more at ease knowing that they could prevent leakage onto their clothes. At present, current appliances do not include this feature. Later on in the survey we will present you with a hypothetical appliance that may vary in three possible ways. Leakage This feature of the appliance relates to the occurrence of leakage from the baseplate onto the clothes. Some appliances can lead to leakage due to poor fit, or poor design of the appliance. The new hypothetical appliance will present three possible outcomes of how often leakage occurs and leads to soiling of the clothes. Filter performance Filters can last for varying periods of time and people can experience filter dysfunction from time to time. Filter dysfunction can be caused by clogging of the filter and cause ballooning or pancaking of the bag, or smell. We will present to you a hypothetical new appliance which will vary in terms of how long the filter lasts. Below are three possible ways in which the appliance will vary in terms of functioning-time of the filter. Service/help after hospital discharge This feature relates to a service that is provided to people after discharge from surgery. People who have received specific appliances are offered a program which allows them to contact specialists for more information or help with their stoma management. We will present you with an appliance that will vary in availability of this program in three possible ways.
Able to detect all leakage episodes Able to detect some leakage episodes Not able to detect leakage
Out of pocket cost of device (for monthly supply of devices) This treatment feature relates to how much more a monthly supply of appliances may cost you over and above your original monthly health insurance payment. Although you may not pay anything for your current appliance, it is possible that you may be willing to pay more for a monthly supply of improved appliances.
£0 UK, 0E France, 0E Germany £25 UK, 25E France, 30E Germany £50 UK, 50E France, 60E Germany
Final survey questionnaire The final survey included questions regarding previous experience of ostomy appliances and the common problems associated with them. Participants were also asked to describe their current appliance in terms of the attributes and levels in the DCE. Among other attributes, the ‘episodes of skin problems’ attribute was described in terms of the number or proportion of people who after ! 2015 Informa UK Ltd www.cmrojournal.com
10/100 people experienced skin complications with the new device (10%) 15/100 people experienced skin complications with the new device (15%) 50/100 people experienced skin complications with the new device (50%)
No soiling of clothes 2/100 plates result in soiling of clothes (2%) 10/100 plates result in soiling of clothes (10%)
Full regular wear-time 2/3 of regular wear-time 1/3 of regular wear-time
Contacted after surgery by stoma care specialist offering support and regular follow-up. Customer services are also available by phone and e-mail for questions/information about the devices (specialist care and phone/email service) Customer services available by phone and e-mail for questions/ information about the device (phone/email service) No personal customer services available for questions/information about the device (no service)
several weeks of using a new ostomy appliance experienced skin complications. The ‘service/help after hospital discharge’ attribute was described in terms of a service that is provided for people after discharge from surgery. This service allows ostomy users to contact specialists for more information or help with their stoma management. The levels varied in terms of the means of help provided (specialist care, phone, email or no service at all). Patient preferences for stoma care appliances Nafees et al.
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The choice questions included a consistency check whereby one of the choices was repeated and reversed. A rationality check was included whereby one choice logically dominated the other choice on all attribute levels. The survey also included two health-related quality of life (HRQL) measures, the EQ-5D (EuroQoL) for current health status, and the Stoma-QoL8 which evaluates HRQL of people with a stoma. The study protocol and all case-report forms, including the final questionnaire, were approved by the Independent Institutional Review Board (A0649-0007).
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Main study sample People reliant on a colostomy, urostomy or ileostomy appliance or device for bowel or urinary management were invited to participate in this study. Participants were recruited in the UK, France and Germany via a Coloplast patient panel and were invited to complete the online questionnaire. A screening procedure was applied to include only participants between 18 and 85 years, residing in the UK, France or Germany, who had been using a colostomy, urostomy or ileostomy bag for at least the last year, and who were able to read, write and understand the target language well. Participants were excluded if they had an acute illness or cognitive impairment that in the opinion of the interviewer would interfere with the study requirements. Participants received remuneration after completing the survey (an Amazon.com voucher to the value of £10 or E10).
Statistical analysis EQ-5D responses were scored using UK preference weights and presented as a single index utility score which represents HRQL on a scale from 0 (equal to dead) to 1.0 (full health). The Stoma-QoL was analyzed in terms of a raw score ranging from 20 to 80 and final scores ranging from 0 to 100 (high scores indicate better functioning). The DCE data were analyzed using a conditional logit model to explore the impact of each attribute on participants’ choices. The conditional logit model evaluates choice responses after conditioning them on the attributes of the other treatment alternatives available within the choice set. Hence, if, for example, ‘Device option A’ is preferred in the choice set #1, this preference is conditional on the attributes of ‘Device option B’. The coefficients obtained from the logit model provide an estimate of the (log) odds ratios of preference for appliance attributes. In addition, interactions in the conditional logit models were explored to see whether there were any country-specific differences in the preferences for each attribute. In the country variable, UK was coded as 0; therefore, the 690
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results can be interpreted as follows: all of the coefficients for the terms without the interaction were the same as the UK only model. The coefficients of the interaction terms were the differences between the UK coefficients and the France and Germany coefficients. The p-value for the interaction term tested the difference between the UK and other country coefficients. In every attribute, the worst level was used as a reference case against all other levels. The profiles showed the likelihood of choosing an appliance and WTP over the base case. The base case appliance was defined as an appliance which had no flexibility and was always uncomfortable, caused skin problems for 50/100 people, was not able to detect leakage, 10/100 baseplates resulted in soiling of clothes, the filter performed 1/3 of regular wear-time, the users were not provided any service after discharge, and would cost £50. WTP for each level of a given attribute was calculated by dividing the estimated coefficients for each attribute by the coefficient for the out-of-pocket cost attribute.
Results Participant characteristics A total of 415 participants (N ¼ 166 UK; N ¼ 99 France, N ¼ 150 Germany) completed all study questionnaires (Table 2). Five participants failed the consistency check in the choice section and were thus excluded from the analyses. A higher percentage of the participants were males (56%) and 82% of the participants were 45 years old. On average, participants had had a stoma for 10 years. One-piece appliance users were highly represented in the sample from UK (73%), whereas most participants from France and Germany used a two-piece (66% and 55% respectively). Most of the participants in each country used a Coloplast appliance. Table 2 also reports summaries of the HRQL data. Participants rated their current treatment in terms of the treatment attributes from the DCE (Table 3). The majority of the sample in each country reported that their current appliance ‘had elastic flexibility’. In France and the UK, more than half of the participants had experienced skin problems previously (53% France and 57% UK), while only 28% in Germany had experienced skin problems. Participants reported a broad range of reasons for changing their baseplate. For one-piece users, the most common reasons were ‘I followed my usual changing pattern’ (29% total sample), ‘leakage under the baseplate’ (36%), and ‘area around the stoma was itching’ (26% total sample). The majority of participants in each country were not paying for their current appliance (99% UK, 94% France, and 60% Germany). www.cmrojournal.com ! 2015 Informa UK Ltd
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Table 2. Socio-demographic profile and clinical history of all participants by country.
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All N ¼ 415
UK N ¼ 166
Age, n (%) 20 to 24 3 (1) 2 (1) 25 to 29 7 (2) 3 (2) 30 to 34 11 (3) 6 (4) 35 to 39 20 (5) 7 (4) 40 to 44 35 (8) 14 (8) 45 to 50 55 (13) 22 (13) 51 to 60 94 (23) 39 (23) 61 and over 190 (46) 73 (44) Gender: Female n (%) 182 (44) 81 (49) Occupation, n (%) Employed (full-time) 87 (21) 46 (28) Employed (part-time) 20 (5) 11 (7) Student 5 (1) 3 (2) Job seeker 9 (2) 0 (0) Unemployed 27 (7) 12 (7) Retired 227 (55) 81 (49) Other 40 (10) 13 (8) EQ-5D Index score, mean (std) 0.79 (0.26) 0.77 (0.30) Stoma-QoL final score, mean (std) 56 (11) 55 (11) Type of ostomy appliance, n (%) Colostomy 166 (40) 56 (34) Ileostomy 174 (42) 84 (51) Urostomy 75 (18) 26 (16) Duration of having stoma (years) Mean (std) 9.89 (8.52) 8.58 (7.99) Appliance currently used, n (%) One-piece 224 (54) 122 (73) Two-piece 191 (46) 44 (27) Open or closed pouch, n (%) Open 275 (66) 121 (73) Closed 121 (29) 39 (23) Both open and closed pouches 19 (5) 6 (4) Use a convex system: yes, n (%) 176 (42) 65 (39) Indicate the manufacturer of the ostomy appliance you currently use*, n (%) Coloplast 339 (82) 135 (81) Convatec 28 (7) 7 (4) Hollister 35 (8) 4 (2) Welland 3 (1) 3 (2) Dansac 18 (4) 7 (4) B.Braun 17 (4) 3 (2) Other 21 (5) 11 (7)
France N ¼ 99
Germany N ¼ 150
0 (0) 2 (2) 3 (3) 5 (5) 3 (3) 7 (7) 20 (20) 59 (60) 40 (40)
1 (1) 2 (1) 2 (1) 8 (5) 18 (12) 26 (17) 35 (23) 58 (39) 61 (41)
6 (6) 2 (2) 1 (1) 2 (2) 14 (14) 61 (62) 13 (13) 0.80 (0.20) 56 (10)
35 (23) 7 (5) 1 (1) 7 (5) 1 (1) 85 (57) 14 (9) 0.81 (0.25) 57 (10)
43 (43) 27 (27) 29 (29)
67 (45) 63 (42) 20 (13)
11.15 (8.65)
10.54 (8.86)
34 (34) 65 (66)
68 (45) 82 (55)
65 (66) 29 (29) 5 (5) 36 (36)
89 (59) 53 (35) 8 (5) 75 (50)
89 (90) 8 (8) 8 (8) 0 (0) 0 (0) 6 (6) 0 (0)
115 (77) 13 (9) 23 (15) 0 (0) 11 (7) 8 (5) 10 (7)
*Participants could select more than one answer.
Discrete choice experiment findings Table 4 presents the results of the DCE in separate models by country.
UK In the UK, all attributes were significant predictors of choice which means that participants were considering each attribute when making choices. However, some levels of an attribute were not significant. The UK sample indicated that comfort and flexibility was the most important attribute and participants were five times more likely to choose a device with the best level of this attribute (odds ratio [OR] ¼ 5.20, 95% confidence interval [CI] ¼ 4.50–6.01). This was followed by ‘skin problems’ ! 2015 Informa UK Ltd www.cmrojournal.com
where participants preferred to choose an appliance which led to least likelihood of skin. British participants did not place any significant value on receiving access to a service program when they first start using their device. Cost of the appliance was also a significant predictor of choice (OR ¼ 1.15, 95% CI ¼ 1.12–1.18) in the UK even though almost no one on the UK paid for their devices.
France Participants in France followed similar patterns of choice to the UK. The French sample placed high value on comfort and flexibility and preferred an appliance which had elastic flexibility and was comfortable (OR ¼ 3.16, 95% CI ¼ 2.66–3.76). Participants in France were over twice as likely to choose a device with a 10% risk of skin Patient preferences for stoma care appliances Nafees et al.
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Table 3. The current appliance profile of all participants by country. Total Patients, N
All N ¼ 415
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Comfort and elastic flexibility, n (%) Has elastic flexibility 318 (77) Very little elastic flexibility 91 (22) No elastic flexibility 6 (1) Experienced skin problems: yes, n (%) 188 (45) Number of times experienced skin complications in the last 12 months*, n (%) Never 5 (3) Once a week 36 (19) More than once a week 40 (21) Once a month 59 (31) Once every 3 months 34 (18) How often do you change your pouch (one-piece users only), n (%) 43 times per day 10 (4) 3 times per day 17 (8) Twice per day 26 (12) Once per day 101 (45) Every second day or less 70 (31) How often do you change your pouch (two-piece users only)*, n (%) At least once per day 96 (50) Every second day 46 (24) Every third day 29 (15) Once a week 7 (4) Most common reason for change of the baseplate (one-piece users only)*, n (%) I followed my usual changing pattern 121 (29) The bag was full 41 (18) I thought it would be nice with a clean product 40 (18) The area around the stoma was itching 59 (26) The area around the stoma was painful 22 (10) There was leakage under the baseplate 80 (36) Most common reason for change of the baseplate (two-piece users only)*, n (%) I followed my usual changing pattern 112 (59) Baseplate did not stick in the outer area 48 (25) Feared that the baseplate would loosen 21 (11) The area around the stoma was itching 68 (36) The area around the stoma was painful 24 (13) There was leakage under the baseplate 62 (32) Leakage onto your clothes in the last 12 months, n (%) Never 98 (24) More than once a week 23 (6) Once a week 34 (8) Once a month 88 (21) More than once every 3 months 28 (7) Once every 3 months 144 (35) Experience a filter dysfunction: yes, n (%) 245 (59) How frequently do you change the bag/appliance due to filter dysfunction, n (%) Never 204 (49) 1 in 20 times (5%) 138 (33) 1 in 10 times (10%) 73 (18) Are you currently paying for your appliances, n (%) Yes paying fully 10 (2) Yes paying partly 57 (14)
UK N ¼ 166
France N ¼ 99
Germany N ¼ 150
129 (78) 36 (22) 1 (1) 94 (57)
66 (67) 30 (30) 3 (3) 52 (53)
123 (82) 25 (17) 2 (1) 42 (28)
3 (3) 18 (19) 18 (19) 32 (34) 18 (19)
0 (0) 9 (17) 10 (19) 15 (29) 11 (21)
2 (5) 9 (21) 12 (29) 12 (29) 5 (12)
7 (6) 7 (6) 8 (7) 52 (43) 48 (39)
0 (0) 5 (15) 8 (24) 13 (38) 8 (24)
3 (4) 5 (7) 10 (15) 36 (53) 14 (21)
19 (43) 13 (30) 6 (14) 3 (7)
26 (40) 18 (28) 13 (20) 2 (3)
51 (62) 15 (18) 10 (12) 2 (2)
69 (42) 24 (20) 26 (21) 41 (34) 17 (14) 54 (44)
24 (24) 7 (21) 8 (24) 7 (21) 0 (0) 11 (32)
28 (19) 10 (15) 6 (9) 11 (16) 5 (7) 15 (22)
30 (68) 8 (18) 6 (14) 15 (34) 6 (14) 15 (34)
41 (63) 21 (32) 4 (6) 24 (37) 9 (14) 20 (31)
41 (50) 19 (23) 11 (13) 29 (35) 9 (11) 27 (33)
31 (19) 10 (6) 15 (9) 38 (23) 12 (7) 60 (36) 104 (63)
14 (14) 4 (4) 11 (11) 26 (26) 8 (8) 36 (36) 50 (51)
53 (35) 9 (6) 8 (5) 24 (16) 8 (5) 48 (32) 91 (61)
81 (49) 57 (34) 28 (17)
52 (53) 30 (30) 17 (17)
71 (47) 51 (34) 28 (19)
0 (0) 1 (1)
0 (0) 6 (6)
10 (7) 50 (33)
*Missing data.
problems compared to one with a 50% risk (OR ¼ 2.29, 95% CI ¼ 1.93–2.72). The sample preferred appliances which were able to detect leakage episodes (OR ¼ 1.98, 95% CI ¼ 1.67–2.35). French participants also preferred appliances which led to no soiling of clothes compared to baseplates with a 10% risk of soiling (OR ¼ 1.55, 95% CI ¼ 1.30–1.85). Participants preferred filters to last the full normal wear-time (OR ¼ 1.48, 95% CI ¼ 1.24–1.76). French participants did not place any significant value on 692
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receiving access to a service program when they first start using their device. Out-of-pocket cost was a significant driver of choice.
Germany In Germany, all attributes had some levels which were significant predictors of choice except service after discharge. This means that some levels of attributes were www.cmrojournal.com ! 2015 Informa UK Ltd
78.65 39.12 – 41.82 32.47 – 12.35 – – 11.82 10.94 – 24.18 – – – – – – 2.661–3.763 1.380–1.923 – 1.932–2.723 1.619–2.235 – 1.081–1.408 0.845–1.110 – 1.069–1.398 1.059–1.371 – 1.309–1.738 0.958–1.243 – 0.957–1.253 0.839–1.099 – 1.156–1.208 3.164* 1.629* – 2.294* 1.902* – 1.234* 0.968 – 1.223* 1.205* – 1.508* 1.091 – 1.095 0.960 – 1.182* 1.164–1.239
64.00 27.11 – 46.11 35.72 – 38.06 16.11 – 24.39 14.00 – 21.67 9.94 – – –
Willingness to pay
Cost
Service after discharge
Filter performance
Leakage
Detection
Episodes of skin problems
yThe worst level of each attribute is the reference case. *Significant at p50.05.
5.202* 2.344* – 1.948* 1.728* – 1.704* 1.209* – 1.348* 1.247* – 1.535* 1.065 – 1.149 0.984 – 1.149* Elastic flexibility and comfortable Little flexibility and a little uncomfortable No flexibility and always uncomfortable (reference) 10/100 people 15/100 people 50/100 people (reference) Able to detect all leakage episodes Able to detect some leakage episodes Not able to detect leakage (reference) No soiling of clothes 2/100 baseplates result in soiling of clothes 10/100 baseplates result in soiling of clothes (reference) Full regular wear-time 2/3 of regular wear-time 1/3 of regular wear-time (reference) Specialist care and phone/email service Phone/email service No service (reference) Per E10 decrease Comfort and flexibility
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significant predictors of choice in comparison to the base case. Similar to the UK and France, the German sample placed high importance on comfort and flexibility with participants being almost four times as likely to prefer a device with the best level on this attribute (OR ¼ 3.81, 95% CI ¼ 3.31–4.38). Participants also placed significant importance on avoiding ‘skin problems’ when using an appliance. Participants were twice as likely to prefer a device with the best level on this attribute (OR ¼ 2.04, 95% CI ¼ 1.78–2.33). The sample preferred an appliance which was able to detect all leakage episodes to an appliance that wasn’t able to detect at all (OR ¼ 1.22, 95% CI ¼ 1.07–1.40). German participants did not place significantly more importance on an appliance which was able to detect some leakage rather than one that was not able to detect any. The German sample preferred appliances which led to no soiling of clothes (OR ¼ 1.22, 95% CI ¼ 1.07–1.40). Both levels of this attribute were significant over the reference case. Participants placed high value in filters lasted for the complete wear-time (OR ¼ 1.51, 95% CI ¼ 1.31–1.74). But participants did not place value on smaller improvements in wear-time. Participants did not value receiving any post-discharge service program. Cost of the appliance was also a significant predictor of choice (OR ¼ 1.18, 95% CI ¼ 1.16–1.21).
3.164* 1.629* – 2.294* 1.902* – 1.984* 1.336* – 1.552* 1.286* – 1.478* 1.195* – 0.929 0.870 – 1.201* 144.88 74.86 – 58.60 48.06 – 46.81 16.69 – 26.27 19.42 – 37.69 – – – – – 4.503–6.010 2.062–2.666 – 1.697–2.236 1.518–1.968 – 1.483–1.958 1.058–1.381 – 1.173–1.549 1.096–1.420 – 1.331–1.772 0.936–1.212 – 0.998–1.323 0.862–1.125 – 1.121–1.178
2.661–3.763 1.380–1.923 – 1.932–2.723 1.619–2.235 – 1.673–2.352 1.130–1.580 – 1.303–1.848 1.093–1.514 – 1.238–1.763 1.015–1.408 – 0.780–1.106 0.735–1.030
95% CI 95% CI WTP (E) 95% CI
Level Parameter
Table 4. Results of conditional logit model for all countriesy.
OR
OR
France UK
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WTP (E)
OR
Germany
WTP (E)
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The WTP values show how much people were willing to pay in addition per month, for each level of improvement compared to the worst case scenario. The WTP estimates of all levels of attributes are presented in Table 4. In the UK, the WTP values ranged from E16.69 (able to detect some leakage episodes) to E144.88 (elastic flexibility and comfortable than no flexibility). In France, the WTP values ranged from E9.94 2/3 of regular wear-time) to E64 (elastic flexibility and comfortable than no flexibility). In Germany, the WTP values ranged from E10.94 (2/100 baseplates result in soiling of clothes) to E78.65 (elastic flexibility and comfortable than no flexibility).
Discussion The current study explored patient preferences of attributes of appliances for stoma care through the use of a stated preference DCE survey. A total of 415 participants completed the survey in the UK, France and Germany. The attributes included comfort and flexibility, episodes of skin problems, detection, leakage, filter performance, service after discharge, and out-of-pocket cost. This is the first study to explore these attributes of stoma appliances in a single study and across these countries. In addition to patient preference data, the survey also collected Patient preferences for stoma care appliances Nafees et al.
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additional data such as background demographics, some clinical data, and data on HRQL. The study revealed that patients had good overall quality of life, as shown by EQ-5D scores. Participants reported on the aspects of appliances that they valued highly in their current appliance, and for future appliances by applying the DCE methodology. The DCE data revealed that comfort and flexibility, episodes of skin problems, and leakage were all important attributes of stoma care for the participants. The data highlight how the issues of most importance to people with ostomy devices are the day to day issues around comfort. This seems to be even more important than avoiding episodes of leakage. The data in Table 3 indicate that about 75% of the sample have experienced leakage on to their clothes in the last 12 months with some people experiencing it as frequently as once a week. Despite experiencing quite high rates of leakage, the participants in this study placed the highest value on improvements in comfort and fit. The study contrasts with previous findings from Sweden. Bonnichsen reported data from 254 participants that evaluated patient preferences in improvements in stoma pouches and explored attributes such as the adhesive, filter, and flexibility9. Participants from the Swedish study placed most value on reducing the number of leakages; followed by comfort and flexibility of the system, and filter lifetime. In the present study, episodes of skin problems were an important attribute for participants and were a significant driver of choice. Skin problems have been shown by several studies to be correlated with HRQL. Patients with peristomal skin disorders report significantly lower HRQL2,10. This is also consistent with Pittman et al.’s study in which skin irritation and leakage were a major driver of choice. Other attributes of appliances were also important for the participants in the present study, with some levels being significantly more important than others. The results showed that filter performance was an important attribute and data relating to previous use of appliances indicated that a high number of participants had experienced a filter dysfunction and leakage. None of the participants showed a significant preference for access to a specialist support service after discharge. In the cognitive debrief interviews, participants in Germany revealed that they have a stoma therapist who provides sufficient information and instructions on using the appliance which may be the reason why participants did not place value in an additional service after discharge. In addition many of the participants in the study had been using their device for many years and so perhaps felt that this service was less relevant for them. It may be better to seek views on the value of such a service from people who are new to ostomy care. Previous research has also highlighted the importance of support and 694
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education in stoma appliances to better use and experience of appliances3. People in all three countries were considering cost when making their choices. This is despite the fact that almost all participants in the UK and most in the other two countries paid nothing for their ostomy appliances. Interestingly, overall participants in the UK were willing to pay more for improvements in attributes than participants from France and Germany. The findings also reveal how much more the participants would be willing to pay for improvements in each level of an attribute and thus may be useful information in the development of future appliances. There are some important limitations to this study which should be considered when reviewing the results. The participants were recruited through a patient panel which largely included patients who used Coloplast products only. Therefore the panel may not be completely representative of ostomy appliance users. The study relied on self-report and participants’ use of ostomy devices was not independently verified in this study. However, the Coloplast panel is specifically designed to support ostomy device users and, as such, only includes people who use such devices. In addition, recruitment was supported by a screener to ensure people were suitable for completing the survey. This screener was designed with clinician input and helped to validate the sample. In addition, data were only collected using an online survey, which may not have suited all potential participants. The findings indicate the aspects of stoma appliances that are important for participants and may determine how they would select an appliance in the future. The data could also be used to compare the relative value of different devices and also the potential value of new devices. The WTP estimates show the value that people place on improvements in the design of devices.
Conclusion In conclusion, this study identified patient preferences for different aspects of stoma appliances in the UK, France and Germany. Comfort and flexibility, episodes of skin problems, detection and leakage were the most important aspects of appliances for participants in all countries and the estimated WTP values is an indicator of the strength of patient preferences.
Transparency Declaration of funding The study was sponsored by Coloplast Ltd. Coloplast also contributed to the design of the study and the preparation of the manuscript.
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Declaration of financial/other relationships B.N. and A.L. have disclosed that they are employees of ICON plc, a company that received funding from Coloplast to conduct this study. E.E. has disclosed that he was an employee of ICON plc at the time this study was conducted. T.P. has disclosed that she is an employee of Coloplast. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.
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Acknowledgments This study was supported by research funding from Coloplast A/S to ICON plc. No restrictions were, however, placed on the design of the study, the choice of included data sources or the presentation of results. The authors specifically thank Mikkel Rasmussen and Martin Nottmeier of Coloplast for contributing to data interpretation and critical scientific review of the manuscript.
References 1. Herlufsen P, Olsen AG, Carlsen B, et al. Study of peristomal skin disorders in patients with permanent stomas. Br J Nurs 2006;15:854-62
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2. Nybaek H, Jemec GB. Skin problems in stoma patients. J Eur Acad Dermatol Venereol 2010;24:249-57 3. Pittman J, Rawl SM, Schmidt C, et al. Demographic and clinical factors related to ostomy complications and quality of life in veterans with an ostomy. J Wound Ostomy Continence Nurs 2008;35:493-503 4. Burch J. Resuming a normal life: holistic care of the person with an ostomy. Br J Community Nursing 2011;16:366-73 5. Colwell J. Principle of stoma management. In: Colwell J, Goldberg M, Carmel J, eds. Fecal & Urinary Diversions: Management Principles, 2nd edn. St. Louis: Mosby, 2004:381-91 6. Sloane NJA. A library of orthogonal arrays. Available at: http://neilsloane.com/ oadir/. Accessed in September 2013 7. Organisation for Economic Co-operation and Development (OECD) StatExtracts. PPPs and exchange rate. 2014. Available at: http://stats.oecd.org/Index.aspx?datasetcode¼SNA_TABLE4. Accessed in September 2013 8. Preito L, Thorson H, Juul K. Development and validation of a quality of life questionnaire for patients with colostomy or ileostomy. Health Qual Life Outcomes 2005;3:62 9. Bonnichsen O. Elicitation of ostomy pouch preferences. A discrete-choice experiment. Patient 2011;4:163-75 10. Davis JS, Svavarsdo´ttir MH, Pudlo M, et al. Factors impairing quality of life for people with an ostomy. Gastrointestinal Nurs 2011;9:14-18
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To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany a
a
b
Beenish Nafees , Andrew Lloyd , Eric Elkin & Terri Porret
c
a a
ICON plc, Oxford, UK
b b
ICON plc, San Francisco, USA
c c
Coloplast UK Ltd, Peterborough, UK Published online: 02 Jul 2015.
Click for updates To cite this article: Beenish Nafees, Andrew Lloyd, Eric Elkin & Terri Porret (2015) To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany, Current Medical Research and Opinion, 31:4, 687-695 To link to this article: http://dx.doi.org/10.1185/03007995.2015.1008688
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Vol. 31, No. 4, 2015, 687–695
Article ST-0350.R1/1008688 All rights reserved: reproduction in whole or part not permitted
Current Medical Research and Opinion 2015.31:687-695.
Original article To explore preferences and willingness to pay for attributes regarding stoma appliances amongst patients in the UK, France and Germany
Beenish Nafees Andrew Lloyd ICON plc, Oxford, UK
Eric Elkin
Abstract Objectives: To explore patient preferences regarding stoma appliances in the UK, France and Germany and to estimate willingness to pay (WTP) for attributes of stoma appliances.
ICON plc, San Francisco, USA
Terri Porret Coloplast UK Ltd, Peterborough, UK Address for correspondence: Beenish Nafees, Senior Outcomes Researcher, Seacourt Tower, West Way, Oxford OX2 0JJ, UK. Tel.: +44 (0)7957 634170; [email protected] Keywords: Discrete choice experiment – Preference – Stoma care Accepted: 13 January 2015; published online: 2 March 2015 Citation: Curr Med Res Opin 2015; 31:687–95
Research design and methods: A discrete choice (DCE) survey was developed based on published literature, attributes of current available appliances and qualitative interviews with patients from the UK (N ¼ 3), France (N ¼ 2) and Germany (N ¼ 2). Members from a patient panel in the UK, France and Germany were asked to participate in the DCE survey and to fill out two quality of life (QoL) questionnaires. Data were analyzed using the conditional logit model whereby the coefficients obtained from the model provided an estimate of the (log) odds ratios (ORs) of preference for attributes. WTP was estimated for each level of a given identified attribute. Results: Seven key attributes were identified for the DCE survey: comfort and elastic flexibility, skin problems, early detection of leakage, leakage, filter performance, service/help after hospital discharge and out-of-pocket cost. A total of 415 participants (166 patients in UK, 99 in France, and 150 in Germany) completed the questionnaires. All attributes were significant predictors of choice. The two most important drivers of preference were the attributes comfort and elastic flexibility and skin problems which resulted in high WTP values. Appliances which were able to detect episodes of leakage were also of high importance to participants’ appliances. Conclusions: The results show the importance of different attributes of stoma appliances for patients. Improving comfort and elastic flexibility, and risk of skin problems were the most important aspects of appliances. The WTP values indicate the value people place on improvement in each attribute of appliances.
Introduction A stoma is a surgically created opening connecting an internal organ to the surface of the body where waste matter can be collected using an ostomy appliance. Living with a stoma is life-changing, where complications such as leakage, skin irritation and loss of bodily function may negatively affect physical wellbeing and health related quality of life (HRQL)1,2. New innovations in stoma care are therefore of great importance for people with a stoma and even small improvements in the functionality or performance of an appliance have been shown to produce important gains in HRQL3. Most ostomy pouching systems are designed to collect stoma output, be odor-free and ! 2015 Informa UK Ltd www.cmrojournal.com
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skin-friendly4. Skin irritation from the use of ostomy devices is an important concern for patients and may affect decisions regarding the choice of devices3,5. Pittman et al. explored how ostomy complications (such as skin irritation, leakage, and difficulty adjusting to an ostomy) affect people’s HRQL through research with 239 US veterans3. Participants completed the City of Hope Quality of Life: Ostomy Instrument (mCOHQOL-Ostomy). Having an ileostomy was associated with higher severity of skin irritation than having a colostomy. The research highlighted the importance of effective communication with patients. Patients who had received education before surgery were significantly less likely to report problems with skin irritation and leakage (p50.01). The research also demonstrated that overall HRQL was predicted by the severity of skin irritation, leakage and difficulty adjusting to the ostomy device. The research from Pittman and others shows the potential for understanding the benefit or value of improvements in ostomy product design by measuring patients’ HRQL1–3. An alternative approach to the assessment of the benefit of new ostomy devices is through the use of patient preference surveys which specifically estimate how much value users place on different aspects of the design. One methodology that has been quite widely used to do this is the discrete choice experiment (DCE), which is a stated preference survey method. A DCE can capture participants’ strength of preference for the characteristics or attributes of a product and can help identify the relative importance of different attributes. We can also understand the degree to which people are willing to trade between the attributes (estimated using marginal rates of substitution). In a DCE study strength of preference can be estimated using willingness to pay (WTP). WTP can be estimated by including out-of-pocket cost as an attribute in the survey and then exploring the extent to which people are willing to trade total cost against improvements in features or design. The aim of the current study was to elicit patient preferences regarding stoma appliances amongst participants in the UK, France and Germany and to estimate willingness to pay for attributes of stoma appliances.
Patients and methods Identification of attributes A literature review, interviews with clinical experts and patients, and a review of characteristics of currently available appliances were undertaken to help identify the important aspects or attributes of stoma care appliances for inclusion in the survey. The literature search was carried out in PubMed, EMBASE and Google Scholar (2001– 2014, in English) and was designed to identify evidence 688
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regarding common and important aspects of stoma appliances such as impact on skin condition, and the risk of leakage. The search strategy identified 10 relevant articles regarding patient HRQL and preferences regarding ostomy devices. Seven preliminary attributes were selected for further examination: comfort and flexibility, skin problems, early detection of leakage, leakage risk, filter life-time, service/help after hospital discharge, and out-of-pocket cost (included to estimate willingness to pay). Levels for each attribute were determined based on the literature search and interviews.
Development of DCE survey A preliminary version of the survey was developed based on these attributes. In the survey, the participants were presented with pairs of hypothetical appliances. An orthogonal fractional factorial design based on a published array was used to specify the combinations of attributes and levels in each choice6. A fold-over design was used to produce the pairs of choices. The pairs present two hypothetical appliances (appliance A or appliance B) and participants were requested to select their preferred appliance and whether they would prefer the hypothetical appliance over the current appliance. The survey consisted of 18 pairs of choice sets and included a consistency check. The survey also collected background socio-demographic information. The survey was translated for use in each country and cost levels were adapted between countries using the purchasing power parity estimates7. Semi-structured interviews with stoma patients from the UK (N ¼ 3), France (N ¼ 2) and Germany (N ¼ 2) were performed to explore their interpretation and understanding of the survey. The participants were asked to discuss each attribute, how it impacts their daily life, their current appliance and their preferences regarding aspects of appliances. They were also asked to suggest improvements and modifications to the survey. Interview data were analyzed and attributes and levels were finalized on the basis of these interviews. The final attributes and selected levels are presented in Table 1. The out-of-pocket cost attribute was described as a hypothetical cost and was described as ‘This treatment feature relates to how much more a monthly supply of appliances may cost you over and above your original monthly health insurance payment. Although you may not pay anything for your current appliance, it is possible that you may be willing to pay more for a monthly supply of improved appliances’. An electronic version of the survey was developed for administration via the web. Attention was paid to address online usability concerns in this process, e.g. ease of navigation online, moving back and forth in the survey, and comprehensiveness. www.cmrojournal.com ! 2015 Informa UK Ltd
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Table 1. Ostomy device attributes and levels with details regarding how the attribute was described. Attribute
Level
Comfort and elastic flexibility This feature relates to the elastic flexibility of the adhesive material that affects the fit between the appliance and your body, and how ‘comfortable’ it is in terms of fit. For this feature, please imagine that you have no soreness or redness around your stoma. Later on in the survey, we will present you with new appliances which will vary in terms of comfort and elastic flexibility. Generally, if the adhesive material has elastic flexibility, it will be better at following the movements of the skin and therefore will be more comfortable. Skin problems People can experience skin problems around the stoma due to problems with various ostomy appliances like leakages leading to faecal matter or urine on the skin. The skin problems may include itchiness, redness, allergic reactions, cuts or stripping of the skin and may lead to you seeking advice from your stoma care nurse.
The device has elastic flexibility, follows natural movements of the skin and is comfortable The device has very little elastic flexibility, the skin partly follows the movements of the device and is a little uncomfortable The device has no elastic flexibility, the skin follows the movements of the device and is always uncomfortable
Early detection of leakage This appliance feature relates to an ostomy appliance which may be able to provide a warning to detect early signs of leakage. This feature would be built into the appliance and would be able to detect all or some episodes of leakage. If it is able to detect leakage, this feature would allow people to feel more at ease knowing that they could prevent leakage onto their clothes. At present, current appliances do not include this feature. Later on in the survey we will present you with a hypothetical appliance that may vary in three possible ways. Leakage This feature of the appliance relates to the occurrence of leakage from the baseplate onto the clothes. Some appliances can lead to leakage due to poor fit, or poor design of the appliance. The new hypothetical appliance will present three possible outcomes of how often leakage occurs and leads to soiling of the clothes. Filter performance Filters can last for varying periods of time and people can experience filter dysfunction from time to time. Filter dysfunction can be caused by clogging of the filter and cause ballooning or pancaking of the bag, or smell. We will present to you a hypothetical new appliance which will vary in terms of how long the filter lasts. Below are three possible ways in which the appliance will vary in terms of functioning-time of the filter. Service/help after hospital discharge This feature relates to a service that is provided to people after discharge from surgery. People who have received specific appliances are offered a program which allows them to contact specialists for more information or help with their stoma management. We will present you with an appliance that will vary in availability of this program in three possible ways.
Able to detect all leakage episodes Able to detect some leakage episodes Not able to detect leakage
Out of pocket cost of device (for monthly supply of devices) This treatment feature relates to how much more a monthly supply of appliances may cost you over and above your original monthly health insurance payment. Although you may not pay anything for your current appliance, it is possible that you may be willing to pay more for a monthly supply of improved appliances.
£0 UK, 0E France, 0E Germany £25 UK, 25E France, 30E Germany £50 UK, 50E France, 60E Germany
Final survey questionnaire The final survey included questions regarding previous experience of ostomy appliances and the common problems associated with them. Participants were also asked to describe their current appliance in terms of the attributes and levels in the DCE. Among other attributes, the ‘episodes of skin problems’ attribute was described in terms of the number or proportion of people who after ! 2015 Informa UK Ltd www.cmrojournal.com
10/100 people experienced skin complications with the new device (10%) 15/100 people experienced skin complications with the new device (15%) 50/100 people experienced skin complications with the new device (50%)
No soiling of clothes 2/100 plates result in soiling of clothes (2%) 10/100 plates result in soiling of clothes (10%)
Full regular wear-time 2/3 of regular wear-time 1/3 of regular wear-time
Contacted after surgery by stoma care specialist offering support and regular follow-up. Customer services are also available by phone and e-mail for questions/information about the devices (specialist care and phone/email service) Customer services available by phone and e-mail for questions/ information about the device (phone/email service) No personal customer services available for questions/information about the device (no service)
several weeks of using a new ostomy appliance experienced skin complications. The ‘service/help after hospital discharge’ attribute was described in terms of a service that is provided for people after discharge from surgery. This service allows ostomy users to contact specialists for more information or help with their stoma management. The levels varied in terms of the means of help provided (specialist care, phone, email or no service at all). Patient preferences for stoma care appliances Nafees et al.
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The choice questions included a consistency check whereby one of the choices was repeated and reversed. A rationality check was included whereby one choice logically dominated the other choice on all attribute levels. The survey also included two health-related quality of life (HRQL) measures, the EQ-5D (EuroQoL) for current health status, and the Stoma-QoL8 which evaluates HRQL of people with a stoma. The study protocol and all case-report forms, including the final questionnaire, were approved by the Independent Institutional Review Board (A0649-0007).
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Main study sample People reliant on a colostomy, urostomy or ileostomy appliance or device for bowel or urinary management were invited to participate in this study. Participants were recruited in the UK, France and Germany via a Coloplast patient panel and were invited to complete the online questionnaire. A screening procedure was applied to include only participants between 18 and 85 years, residing in the UK, France or Germany, who had been using a colostomy, urostomy or ileostomy bag for at least the last year, and who were able to read, write and understand the target language well. Participants were excluded if they had an acute illness or cognitive impairment that in the opinion of the interviewer would interfere with the study requirements. Participants received remuneration after completing the survey (an Amazon.com voucher to the value of £10 or E10).
Statistical analysis EQ-5D responses were scored using UK preference weights and presented as a single index utility score which represents HRQL on a scale from 0 (equal to dead) to 1.0 (full health). The Stoma-QoL was analyzed in terms of a raw score ranging from 20 to 80 and final scores ranging from 0 to 100 (high scores indicate better functioning). The DCE data were analyzed using a conditional logit model to explore the impact of each attribute on participants’ choices. The conditional logit model evaluates choice responses after conditioning them on the attributes of the other treatment alternatives available within the choice set. Hence, if, for example, ‘Device option A’ is preferred in the choice set #1, this preference is conditional on the attributes of ‘Device option B’. The coefficients obtained from the logit model provide an estimate of the (log) odds ratios of preference for appliance attributes. In addition, interactions in the conditional logit models were explored to see whether there were any country-specific differences in the preferences for each attribute. In the country variable, UK was coded as 0; therefore, the 690
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results can be interpreted as follows: all of the coefficients for the terms without the interaction were the same as the UK only model. The coefficients of the interaction terms were the differences between the UK coefficients and the France and Germany coefficients. The p-value for the interaction term tested the difference between the UK and other country coefficients. In every attribute, the worst level was used as a reference case against all other levels. The profiles showed the likelihood of choosing an appliance and WTP over the base case. The base case appliance was defined as an appliance which had no flexibility and was always uncomfortable, caused skin problems for 50/100 people, was not able to detect leakage, 10/100 baseplates resulted in soiling of clothes, the filter performed 1/3 of regular wear-time, the users were not provided any service after discharge, and would cost £50. WTP for each level of a given attribute was calculated by dividing the estimated coefficients for each attribute by the coefficient for the out-of-pocket cost attribute.
Results Participant characteristics A total of 415 participants (N ¼ 166 UK; N ¼ 99 France, N ¼ 150 Germany) completed all study questionnaires (Table 2). Five participants failed the consistency check in the choice section and were thus excluded from the analyses. A higher percentage of the participants were males (56%) and 82% of the participants were 45 years old. On average, participants had had a stoma for 10 years. One-piece appliance users were highly represented in the sample from UK (73%), whereas most participants from France and Germany used a two-piece (66% and 55% respectively). Most of the participants in each country used a Coloplast appliance. Table 2 also reports summaries of the HRQL data. Participants rated their current treatment in terms of the treatment attributes from the DCE (Table 3). The majority of the sample in each country reported that their current appliance ‘had elastic flexibility’. In France and the UK, more than half of the participants had experienced skin problems previously (53% France and 57% UK), while only 28% in Germany had experienced skin problems. Participants reported a broad range of reasons for changing their baseplate. For one-piece users, the most common reasons were ‘I followed my usual changing pattern’ (29% total sample), ‘leakage under the baseplate’ (36%), and ‘area around the stoma was itching’ (26% total sample). The majority of participants in each country were not paying for their current appliance (99% UK, 94% France, and 60% Germany). www.cmrojournal.com ! 2015 Informa UK Ltd
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Table 2. Socio-demographic profile and clinical history of all participants by country.
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All N ¼ 415
UK N ¼ 166
Age, n (%) 20 to 24 3 (1) 2 (1) 25 to 29 7 (2) 3 (2) 30 to 34 11 (3) 6 (4) 35 to 39 20 (5) 7 (4) 40 to 44 35 (8) 14 (8) 45 to 50 55 (13) 22 (13) 51 to 60 94 (23) 39 (23) 61 and over 190 (46) 73 (44) Gender: Female n (%) 182 (44) 81 (49) Occupation, n (%) Employed (full-time) 87 (21) 46 (28) Employed (part-time) 20 (5) 11 (7) Student 5 (1) 3 (2) Job seeker 9 (2) 0 (0) Unemployed 27 (7) 12 (7) Retired 227 (55) 81 (49) Other 40 (10) 13 (8) EQ-5D Index score, mean (std) 0.79 (0.26) 0.77 (0.30) Stoma-QoL final score, mean (std) 56 (11) 55 (11) Type of ostomy appliance, n (%) Colostomy 166 (40) 56 (34) Ileostomy 174 (42) 84 (51) Urostomy 75 (18) 26 (16) Duration of having stoma (years) Mean (std) 9.89 (8.52) 8.58 (7.99) Appliance currently used, n (%) One-piece 224 (54) 122 (73) Two-piece 191 (46) 44 (27) Open or closed pouch, n (%) Open 275 (66) 121 (73) Closed 121 (29) 39 (23) Both open and closed pouches 19 (5) 6 (4) Use a convex system: yes, n (%) 176 (42) 65 (39) Indicate the manufacturer of the ostomy appliance you currently use*, n (%) Coloplast 339 (82) 135 (81) Convatec 28 (7) 7 (4) Hollister 35 (8) 4 (2) Welland 3 (1) 3 (2) Dansac 18 (4) 7 (4) B.Braun 17 (4) 3 (2) Other 21 (5) 11 (7)
France N ¼ 99
Germany N ¼ 150
0 (0) 2 (2) 3 (3) 5 (5) 3 (3) 7 (7) 20 (20) 59 (60) 40 (40)
1 (1) 2 (1) 2 (1) 8 (5) 18 (12) 26 (17) 35 (23) 58 (39) 61 (41)
6 (6) 2 (2) 1 (1) 2 (2) 14 (14) 61 (62) 13 (13) 0.80 (0.20) 56 (10)
35 (23) 7 (5) 1 (1) 7 (5) 1 (1) 85 (57) 14 (9) 0.81 (0.25) 57 (10)
43 (43) 27 (27) 29 (29)
67 (45) 63 (42) 20 (13)
11.15 (8.65)
10.54 (8.86)
34 (34) 65 (66)
68 (45) 82 (55)
65 (66) 29 (29) 5 (5) 36 (36)
89 (59) 53 (35) 8 (5) 75 (50)
89 (90) 8 (8) 8 (8) 0 (0) 0 (0) 6 (6) 0 (0)
115 (77) 13 (9) 23 (15) 0 (0) 11 (7) 8 (5) 10 (7)
*Participants could select more than one answer.
Discrete choice experiment findings Table 4 presents the results of the DCE in separate models by country.
UK In the UK, all attributes were significant predictors of choice which means that participants were considering each attribute when making choices. However, some levels of an attribute were not significant. The UK sample indicated that comfort and flexibility was the most important attribute and participants were five times more likely to choose a device with the best level of this attribute (odds ratio [OR] ¼ 5.20, 95% confidence interval [CI] ¼ 4.50–6.01). This was followed by ‘skin problems’ ! 2015 Informa UK Ltd www.cmrojournal.com
where participants preferred to choose an appliance which led to least likelihood of skin. British participants did not place any significant value on receiving access to a service program when they first start using their device. Cost of the appliance was also a significant predictor of choice (OR ¼ 1.15, 95% CI ¼ 1.12–1.18) in the UK even though almost no one on the UK paid for their devices.
France Participants in France followed similar patterns of choice to the UK. The French sample placed high value on comfort and flexibility and preferred an appliance which had elastic flexibility and was comfortable (OR ¼ 3.16, 95% CI ¼ 2.66–3.76). Participants in France were over twice as likely to choose a device with a 10% risk of skin Patient preferences for stoma care appliances Nafees et al.
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Table 3. The current appliance profile of all participants by country. Total Patients, N
All N ¼ 415
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Comfort and elastic flexibility, n (%) Has elastic flexibility 318 (77) Very little elastic flexibility 91 (22) No elastic flexibility 6 (1) Experienced skin problems: yes, n (%) 188 (45) Number of times experienced skin complications in the last 12 months*, n (%) Never 5 (3) Once a week 36 (19) More than once a week 40 (21) Once a month 59 (31) Once every 3 months 34 (18) How often do you change your pouch (one-piece users only), n (%) 43 times per day 10 (4) 3 times per day 17 (8) Twice per day 26 (12) Once per day 101 (45) Every second day or less 70 (31) How often do you change your pouch (two-piece users only)*, n (%) At least once per day 96 (50) Every second day 46 (24) Every third day 29 (15) Once a week 7 (4) Most common reason for change of the baseplate (one-piece users only)*, n (%) I followed my usual changing pattern 121 (29) The bag was full 41 (18) I thought it would be nice with a clean product 40 (18) The area around the stoma was itching 59 (26) The area around the stoma was painful 22 (10) There was leakage under the baseplate 80 (36) Most common reason for change of the baseplate (two-piece users only)*, n (%) I followed my usual changing pattern 112 (59) Baseplate did not stick in the outer area 48 (25) Feared that the baseplate would loosen 21 (11) The area around the stoma was itching 68 (36) The area around the stoma was painful 24 (13) There was leakage under the baseplate 62 (32) Leakage onto your clothes in the last 12 months, n (%) Never 98 (24) More than once a week 23 (6) Once a week 34 (8) Once a month 88 (21) More than once every 3 months 28 (7) Once every 3 months 144 (35) Experience a filter dysfunction: yes, n (%) 245 (59) How frequently do you change the bag/appliance due to filter dysfunction, n (%) Never 204 (49) 1 in 20 times (5%) 138 (33) 1 in 10 times (10%) 73 (18) Are you currently paying for your appliances, n (%) Yes paying fully 10 (2) Yes paying partly 57 (14)
UK N ¼ 166
France N ¼ 99
Germany N ¼ 150
129 (78) 36 (22) 1 (1) 94 (57)
66 (67) 30 (30) 3 (3) 52 (53)
123 (82) 25 (17) 2 (1) 42 (28)
3 (3) 18 (19) 18 (19) 32 (34) 18 (19)
0 (0) 9 (17) 10 (19) 15 (29) 11 (21)
2 (5) 9 (21) 12 (29) 12 (29) 5 (12)
7 (6) 7 (6) 8 (7) 52 (43) 48 (39)
0 (0) 5 (15) 8 (24) 13 (38) 8 (24)
3 (4) 5 (7) 10 (15) 36 (53) 14 (21)
19 (43) 13 (30) 6 (14) 3 (7)
26 (40) 18 (28) 13 (20) 2 (3)
51 (62) 15 (18) 10 (12) 2 (2)
69 (42) 24 (20) 26 (21) 41 (34) 17 (14) 54 (44)
24 (24) 7 (21) 8 (24) 7 (21) 0 (0) 11 (32)
28 (19) 10 (15) 6 (9) 11 (16) 5 (7) 15 (22)
30 (68) 8 (18) 6 (14) 15 (34) 6 (14) 15 (34)
41 (63) 21 (32) 4 (6) 24 (37) 9 (14) 20 (31)
41 (50) 19 (23) 11 (13) 29 (35) 9 (11) 27 (33)
31 (19) 10 (6) 15 (9) 38 (23) 12 (7) 60 (36) 104 (63)
14 (14) 4 (4) 11 (11) 26 (26) 8 (8) 36 (36) 50 (51)
53 (35) 9 (6) 8 (5) 24 (16) 8 (5) 48 (32) 91 (61)
81 (49) 57 (34) 28 (17)
52 (53) 30 (30) 17 (17)
71 (47) 51 (34) 28 (19)
0 (0) 1 (1)
0 (0) 6 (6)
10 (7) 50 (33)
*Missing data.
problems compared to one with a 50% risk (OR ¼ 2.29, 95% CI ¼ 1.93–2.72). The sample preferred appliances which were able to detect leakage episodes (OR ¼ 1.98, 95% CI ¼ 1.67–2.35). French participants also preferred appliances which led to no soiling of clothes compared to baseplates with a 10% risk of soiling (OR ¼ 1.55, 95% CI ¼ 1.30–1.85). Participants preferred filters to last the full normal wear-time (OR ¼ 1.48, 95% CI ¼ 1.24–1.76). French participants did not place any significant value on 692
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receiving access to a service program when they first start using their device. Out-of-pocket cost was a significant driver of choice.
Germany In Germany, all attributes had some levels which were significant predictors of choice except service after discharge. This means that some levels of attributes were www.cmrojournal.com ! 2015 Informa UK Ltd
78.65 39.12 – 41.82 32.47 – 12.35 – – 11.82 10.94 – 24.18 – – – – – – 2.661–3.763 1.380–1.923 – 1.932–2.723 1.619–2.235 – 1.081–1.408 0.845–1.110 – 1.069–1.398 1.059–1.371 – 1.309–1.738 0.958–1.243 – 0.957–1.253 0.839–1.099 – 1.156–1.208 3.164* 1.629* – 2.294* 1.902* – 1.234* 0.968 – 1.223* 1.205* – 1.508* 1.091 – 1.095 0.960 – 1.182* 1.164–1.239
64.00 27.11 – 46.11 35.72 – 38.06 16.11 – 24.39 14.00 – 21.67 9.94 – – –
Willingness to pay
Cost
Service after discharge
Filter performance
Leakage
Detection
Episodes of skin problems
yThe worst level of each attribute is the reference case. *Significant at p50.05.
5.202* 2.344* – 1.948* 1.728* – 1.704* 1.209* – 1.348* 1.247* – 1.535* 1.065 – 1.149 0.984 – 1.149* Elastic flexibility and comfortable Little flexibility and a little uncomfortable No flexibility and always uncomfortable (reference) 10/100 people 15/100 people 50/100 people (reference) Able to detect all leakage episodes Able to detect some leakage episodes Not able to detect leakage (reference) No soiling of clothes 2/100 baseplates result in soiling of clothes 10/100 baseplates result in soiling of clothes (reference) Full regular wear-time 2/3 of regular wear-time 1/3 of regular wear-time (reference) Specialist care and phone/email service Phone/email service No service (reference) Per E10 decrease Comfort and flexibility
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significant predictors of choice in comparison to the base case. Similar to the UK and France, the German sample placed high importance on comfort and flexibility with participants being almost four times as likely to prefer a device with the best level on this attribute (OR ¼ 3.81, 95% CI ¼ 3.31–4.38). Participants also placed significant importance on avoiding ‘skin problems’ when using an appliance. Participants were twice as likely to prefer a device with the best level on this attribute (OR ¼ 2.04, 95% CI ¼ 1.78–2.33). The sample preferred an appliance which was able to detect all leakage episodes to an appliance that wasn’t able to detect at all (OR ¼ 1.22, 95% CI ¼ 1.07–1.40). German participants did not place significantly more importance on an appliance which was able to detect some leakage rather than one that was not able to detect any. The German sample preferred appliances which led to no soiling of clothes (OR ¼ 1.22, 95% CI ¼ 1.07–1.40). Both levels of this attribute were significant over the reference case. Participants placed high value in filters lasted for the complete wear-time (OR ¼ 1.51, 95% CI ¼ 1.31–1.74). But participants did not place value on smaller improvements in wear-time. Participants did not value receiving any post-discharge service program. Cost of the appliance was also a significant predictor of choice (OR ¼ 1.18, 95% CI ¼ 1.16–1.21).
3.164* 1.629* – 2.294* 1.902* – 1.984* 1.336* – 1.552* 1.286* – 1.478* 1.195* – 0.929 0.870 – 1.201* 144.88 74.86 – 58.60 48.06 – 46.81 16.69 – 26.27 19.42 – 37.69 – – – – – 4.503–6.010 2.062–2.666 – 1.697–2.236 1.518–1.968 – 1.483–1.958 1.058–1.381 – 1.173–1.549 1.096–1.420 – 1.331–1.772 0.936–1.212 – 0.998–1.323 0.862–1.125 – 1.121–1.178
2.661–3.763 1.380–1.923 – 1.932–2.723 1.619–2.235 – 1.673–2.352 1.130–1.580 – 1.303–1.848 1.093–1.514 – 1.238–1.763 1.015–1.408 – 0.780–1.106 0.735–1.030
95% CI 95% CI WTP (E) 95% CI
Level Parameter
Table 4. Results of conditional logit model for all countriesy.
OR
OR
France UK
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WTP (E)
OR
Germany
WTP (E)
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The WTP values show how much people were willing to pay in addition per month, for each level of improvement compared to the worst case scenario. The WTP estimates of all levels of attributes are presented in Table 4. In the UK, the WTP values ranged from E16.69 (able to detect some leakage episodes) to E144.88 (elastic flexibility and comfortable than no flexibility). In France, the WTP values ranged from E9.94 2/3 of regular wear-time) to E64 (elastic flexibility and comfortable than no flexibility). In Germany, the WTP values ranged from E10.94 (2/100 baseplates result in soiling of clothes) to E78.65 (elastic flexibility and comfortable than no flexibility).
Discussion The current study explored patient preferences of attributes of appliances for stoma care through the use of a stated preference DCE survey. A total of 415 participants completed the survey in the UK, France and Germany. The attributes included comfort and flexibility, episodes of skin problems, detection, leakage, filter performance, service after discharge, and out-of-pocket cost. This is the first study to explore these attributes of stoma appliances in a single study and across these countries. In addition to patient preference data, the survey also collected Patient preferences for stoma care appliances Nafees et al.
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additional data such as background demographics, some clinical data, and data on HRQL. The study revealed that patients had good overall quality of life, as shown by EQ-5D scores. Participants reported on the aspects of appliances that they valued highly in their current appliance, and for future appliances by applying the DCE methodology. The DCE data revealed that comfort and flexibility, episodes of skin problems, and leakage were all important attributes of stoma care for the participants. The data highlight how the issues of most importance to people with ostomy devices are the day to day issues around comfort. This seems to be even more important than avoiding episodes of leakage. The data in Table 3 indicate that about 75% of the sample have experienced leakage on to their clothes in the last 12 months with some people experiencing it as frequently as once a week. Despite experiencing quite high rates of leakage, the participants in this study placed the highest value on improvements in comfort and fit. The study contrasts with previous findings from Sweden. Bonnichsen reported data from 254 participants that evaluated patient preferences in improvements in stoma pouches and explored attributes such as the adhesive, filter, and flexibility9. Participants from the Swedish study placed most value on reducing the number of leakages; followed by comfort and flexibility of the system, and filter lifetime. In the present study, episodes of skin problems were an important attribute for participants and were a significant driver of choice. Skin problems have been shown by several studies to be correlated with HRQL. Patients with peristomal skin disorders report significantly lower HRQL2,10. This is also consistent with Pittman et al.’s study in which skin irritation and leakage were a major driver of choice. Other attributes of appliances were also important for the participants in the present study, with some levels being significantly more important than others. The results showed that filter performance was an important attribute and data relating to previous use of appliances indicated that a high number of participants had experienced a filter dysfunction and leakage. None of the participants showed a significant preference for access to a specialist support service after discharge. In the cognitive debrief interviews, participants in Germany revealed that they have a stoma therapist who provides sufficient information and instructions on using the appliance which may be the reason why participants did not place value in an additional service after discharge. In addition many of the participants in the study had been using their device for many years and so perhaps felt that this service was less relevant for them. It may be better to seek views on the value of such a service from people who are new to ostomy care. Previous research has also highlighted the importance of support and 694
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education in stoma appliances to better use and experience of appliances3. People in all three countries were considering cost when making their choices. This is despite the fact that almost all participants in the UK and most in the other two countries paid nothing for their ostomy appliances. Interestingly, overall participants in the UK were willing to pay more for improvements in attributes than participants from France and Germany. The findings also reveal how much more the participants would be willing to pay for improvements in each level of an attribute and thus may be useful information in the development of future appliances. There are some important limitations to this study which should be considered when reviewing the results. The participants were recruited through a patient panel which largely included patients who used Coloplast products only. Therefore the panel may not be completely representative of ostomy appliance users. The study relied on self-report and participants’ use of ostomy devices was not independently verified in this study. However, the Coloplast panel is specifically designed to support ostomy device users and, as such, only includes people who use such devices. In addition, recruitment was supported by a screener to ensure people were suitable for completing the survey. This screener was designed with clinician input and helped to validate the sample. In addition, data were only collected using an online survey, which may not have suited all potential participants. The findings indicate the aspects of stoma appliances that are important for participants and may determine how they would select an appliance in the future. The data could also be used to compare the relative value of different devices and also the potential value of new devices. The WTP estimates show the value that people place on improvements in the design of devices.
Conclusion In conclusion, this study identified patient preferences for different aspects of stoma appliances in the UK, France and Germany. Comfort and flexibility, episodes of skin problems, detection and leakage were the most important aspects of appliances for participants in all countries and the estimated WTP values is an indicator of the strength of patient preferences.
Transparency Declaration of funding The study was sponsored by Coloplast Ltd. Coloplast also contributed to the design of the study and the preparation of the manuscript.
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Declaration of financial/other relationships B.N. and A.L. have disclosed that they are employees of ICON plc, a company that received funding from Coloplast to conduct this study. E.E. has disclosed that he was an employee of ICON plc at the time this study was conducted. T.P. has disclosed that she is an employee of Coloplast. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.
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Acknowledgments This study was supported by research funding from Coloplast A/S to ICON plc. No restrictions were, however, placed on the design of the study, the choice of included data sources or the presentation of results. The authors specifically thank Mikkel Rasmussen and Martin Nottmeier of Coloplast for contributing to data interpretation and critical scientific review of the manuscript.
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2. Nybaek H, Jemec GB. Skin problems in stoma patients. J Eur Acad Dermatol Venereol 2010;24:249-57 3. Pittman J, Rawl SM, Schmidt C, et al. Demographic and clinical factors related to ostomy complications and quality of life in veterans with an ostomy. J Wound Ostomy Continence Nurs 2008;35:493-503 4. Burch J. Resuming a normal life: holistic care of the person with an ostomy. Br J Community Nursing 2011;16:366-73 5. Colwell J. Principle of stoma management. In: Colwell J, Goldberg M, Carmel J, eds. Fecal & Urinary Diversions: Management Principles, 2nd edn. St. Louis: Mosby, 2004:381-91 6. Sloane NJA. A library of orthogonal arrays. Available at: http://neilsloane.com/ oadir/. Accessed in September 2013 7. Organisation for Economic Co-operation and Development (OECD) StatExtracts. PPPs and exchange rate. 2014. Available at: http://stats.oecd.org/Index.aspx?datasetcode¼SNA_TABLE4. Accessed in September 2013 8. Preito L, Thorson H, Juul K. Development and validation of a quality of life questionnaire for patients with colostomy or ileostomy. Health Qual Life Outcomes 2005;3:62 9. Bonnichsen O. Elicitation of ostomy pouch preferences. A discrete-choice experiment. Patient 2011;4:163-75 10. Davis JS, Svavarsdo´ttir MH, Pudlo M, et al. Factors impairing quality of life for people with an ostomy. Gastrointestinal Nurs 2011;9:14-18
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