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Nutrition in Clinical Care

Dietary educational interventions for management of hyperphosphatemia in hemodialysis patients: a systematic review and meta-analysis Mirey Karavetian, Nanne de Vries, Rana Rizk, and Hafez Elzein Strategies to enhance knowledge of and adherence to dietary guidelines for management of hyperphosphatemia in hemodialysis patients have been studied extensively over the past decade. This review is the first to compile all of them (2003–2013) and conduct a meta-analysis through calculation of effect size, with the aim of identifying the optimal nutrition education methods for effective management of hyperphosphatemia in hemodialysis patients. The following strategies were identified as being effective in changing dietary behavior: 1) use of self-evaluation and self-regulation techniques within educational tools, along with easy-to-apply skills; 2) individualized counseling by a renal dietitian provided just before the hemodialysis session; 3) high-intensity education; and 4) long duration of interventions. Future studies should focus on conducting randomized controlled trials with powered samples to help generate stronger evidence. © 2014 International Life Sciences Institute

INTRODUCTION Hyperphosphatemia is the leading cause of mineral bone disorder in chronic kidney disease1 and of cardiovascular mortality risk among hemodialysis patients.2–5 Achieving optimal serum phosphorus through phosphorusrestricted diets (800–1,000 mg/day) remains the cornerstone of treating mineral bone disorder-hemodialysis,6,7 yet adhering to the recommended phosphorus levels has been reported by hemodialysis patients to be the most complicated of all the dietary restriction-related tasks.8,9 Research about effective strategies to achieve optimal dietary adherence to a phosphorus-restricted diet in hemodialysis patients has been explored in numerous articles over the past decade, and many evidence-based guidelines have been published. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI)6 and the Kidney Disease: Improving Global Outcomes (KDIGO) foundation10 recommend that patients be provided with consistent and frequent dietary

consultations with experts as well as regular follow-up in the context of a nutrition education program. Moreover, 2 hours per patient per month for 12 months has been shown to be an effective dietitian-to-renal-patient consultation time to achieve adherence to a phosphorusrestricted diet.11 However, none of the guidelines prescribed explained the educational strategies needed to achieve optimal adherence. The objective of this review is to examine published nutritional education interventions aimed at improving serum phosphorus levels in hemodialysis patients by enhancing their knowledge of and adherence to dietary instructions related to phosphorus restriction. METHODS The search methodology was developed to retrieve educational dietary interventions directed at the management of hyperphosphatemia (mineral bone disorderhemodialysis) in hemodialysis patients. A search was

Affiliations: M Karavetian and N de Vries are with the Department of Health Promotion, Maastricht University, Maastricht, The Netherlands. R Rizk is with the Department of Human Nutrition and Dietetics, Holy Spirit University of Kaslik, Kaslik, Lebanon. H Elzein is with the Lebanese National Kidney Registry, Beirut, Lebanon. Correspondence: M Karavetian, Department of Health Promotion, Maastricht University, 6200 MD Maastricht, The Netherlands. E-mail: [email protected]. Phone: +971-56-244-6865. Fax: +971-4-402-1018. Key words: dietary education, hemodialysis, hyperphosphatemia management doi:10.1111/nure.12115 Nutrition Reviews®

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Figure 1 Flow diagram of study selection.

conducted using the PubMed, Medline, and Embase databases on June 23, 2013. Only articles published in the past 10 years were included, thus ensuring the search covered the most recent findings on this topic. The search strategy included the following terms and key words selected from the Medical Subject Headings of the National Library of Medicine: phosphates/blood, phosphorus/blood, counseling, education, intervention, diet, nutrition, and hemodialysis. The following key words were also used: phosphate, phosphorous, osteodystrophy, counsel*, educat*, intervention, diet*, and renal dialysis*; whereby, an asterisk (*) indicated that the word before it would be searched in all its versions. The search was run using different Boolean operators (AND, OR), and the complete search string was as follows: (renal dialysis.ab,ti. or exp Renal Dialysis/) AND (exp Diet/or diet*.ab,ti.) AND ((exp Education/or educat*.ab,ti.) OR (counsel*.ab,ti. or exp Counseling/) OR (intervention.ab,ti. or exp Intervention Studies/)) AND ((phosphate.ab,ti. or exp Phosphates/) OR (phosphorus.ab,ti. or exp Phosphorus/)). A total of 240 articles were initially located, with 106 retrieved from PubMed, 81 from Medline, and 53 from 2

Embase. Two more articles were identified through the reference lists of retrieved articles. The removal of duplicate studies resulted in 138 unique reports, of which 18 were included in the analysis, as outlined in Figure 1. The abstracts of all articles were evaluated by two reviewers who followed the same criteria for the selection of articles: 1) hemodialysis as a defining criterion of renal disease in participants; 2) serum phosphorus as the primary outcome; 3) a focus on serum phosphorus management; 4) inclusion of an educational component; 5) the use of any kind of diet-related educational or counseling intervention in the intervention group; 6) patient age ≥18 years; and 7) studies that had active, passive (standard practice), or no comparators. Data extracted included sample size, study design, educational techniques, and results. The extraction was conducted by two reviewers, separately, with agreement reached through discussion. Moreover, serum phosphorus was chosen as the main indicator of dietary adherence, since the KDIGO7 guidelines indicate it is the key outcome measure in managing hyperphosphatemia and osteodystrophy in hemodialysis patients. Nutrition Reviews®

Data analysis To enable comparison among studies, all serum phosphorus values were converted to mg/dL (conversion ratio: 1 mmol/L = 3.095 mg/dL)12; thus, the results of all the reviewed studies are presented in the same unit of measure. The effect size (ES) for each study was calculated, when possible, to evaluate the effectiveness of the strategy used. The calculation of ES was based on the work of Thalheimer and Cook,13 whereby the relative size of Cohen’s d was defined according to the following four levels: d of less than 0.2 was a negligible effect, over 0.2 was a small effect, over 0.5 was a medium effect, and over 0.8 was a large effect. Effect sizes were calculated for 10 of the 18 studies; for the remaining studies, effect sizes could not be calculated, primarily due to the lack of a control group. RESULTS Based on the above-mentioned criteria, 27 of the 138 articles selected for screening were suitable for full-text evaluation; 9 of these were excluded after full-text assessment. Thus, 18 studies with a structured educational intervention met the inclusion criteria. The main characteristics of all studies are presented in Table 1.14–31 Except for the study of Karamanidou et al.,27 all of the studies reported a reduction in serum phosphorus, of which 13 reported a significant improvement. The change varied from 0.3 mg/dL to 1.6 mg/dL (average: 1 mg/dL). Eight of the studies achieved the K/DOQI serum phosphorus target level of ≤5.5 mg/dL post intervention.14– 17,19,23,26,29

Nine of the studies were randomized controlled trials (RCTs),14,16–22,27 two were quasi-experimental,15,30 six were interventional studies without a control,23–25,28,29,31 and one was a retrospective observational study without a control.26 The average age of participants was 55 years (range, 18–88 years). In most studies, there was roughly an equal distribution across gender groups, except in the following studies: Sevick et al.,30 20% male; Morey et al.,22 73% male; and Ford et al.,15 35% male. Ten of the studies included only hyperphosphatemic subjects in their sample14,15,17–22,28,31; as for the rest, the sample was randomly chosen from all patients in the hemodialysis unit. Most studies had a small sample size that ranged from 17 to 45 patients per group. There were, however, several exceptions: the study of Sullivan et al.21 had a sample size of around 140 per group, and three other studies24,25,29 had sample sizes ranging from 115 to 702 patients, but lacked a control group. The following behavioral theories were used as a basis for intervention modeling: 1) Leventhal’s selfNutrition Reviews®

regulatory theory16,27; 2) motivational counseling22; and 3) social cognitive theory.30 Of these, only Leventhal’s selfregulatory theory, as employed by Karavetian and Ghaddar,16 resulted in a significant decrease in patients’ serum phosphorus levels. Morey et al.22 showed a beneficial effect in the short term (month 3), although the significant decrease in serum phosphorus resolved at the end of the intervention (month 6). The duration of each educational session was 20–40 minutes, and the number of those sessions varied from one time in total to eight times per month. The duration of the full intervention varied from 1 month to 6 months: four of the studies15,18,19,22 educated the patients on a monthly basis for 6 months, and three others16,17,30 adopted weekly education sessions for 1–4 months. In 11 of the 18 studies, a renal dietitian was the only educator of the patients14–16,19,21,22,24–26,29,31; in the remaining studies, education was carried out by both a renal nurse and a renal dietitian,30 a renal nurse only,17,23,28 or a renal dietitian and a pharmacist.18 In two studies,20,27 the type of the educator was unclear. There was no specific trend in the reviewed articles regarding the intensity of the education given or the type of the educator (renal dietitian, renal nurse, or pharmacist) in terms of the effect on serum phosphorus. In 16 of the 18 studies, the education of patients took place during the hemodialysis session itself. 15–19,21–31 The study with the strongest improvement in serum phosphorus14 was unique in the timing of the education provided to the patients, i.e., just prior to the hemodialysis session. The only other study to share this timing protocol was that of de Araujo et al.20 The findings of de Araujo et al.20 showed significant improvement in serum phosphorus, but patients were educated on six different occasions, so the improvement may have been the result of the high intensity of the education. Further confirmation of the effect of timing was provided by the study of Baraz et al.,23 in which two different education timings were tested: one during the hemodialysis session and another on the day after the hemodialysis session. Results showed no advantage of one over the other. Individualized education was used by 14 studies.14–19,21,22,24,26–28,30,31 Of these, all except one27 reported improvement in serum phosphorus. Group education was used by four studies, all of which reported significant improvement in serum phosphorus: 1) Reddy et al.25 used a one-time educational audio cassette and booklet; 2) Nisio et al.29 used a onetime educational booklet; 3) de Araujo et al.20 organized a relatively intense group education (frequent meetings and various methods of educational material); and 4) Baraz et al.23 compared the effect of group education conducted the day after the hemodialysis session with individualized education conducted during the hemodialysis 3

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RCT Intervention: 24 wks; 20–30 min session, 2–3 times a week of nurse-led intensive individualized education by trained and experienced nephrology nurse. FU: None Setting: 2 hospital-based HD units

I (n = 40), C (n = 40), both hyperphosphatemics; Age in yrs ± SD: I: 54.75 ± 11.86 C: 51.85 ± 13.51 Gender: I: 52.5% M C: 57.5% M I (n = 17), C (n = 17), both hyperphosphatemics; Age in yrs ± SD: I: 51.1 ± 12.7 C: 47.6 ± 14.4 Gender: I: 55% M C: 60% M I (n = 41), C (n = 39), both hyperphosphatemics; Age in yrs ± SD: I: 61.3 ± 15, C: 63 ± 16 Gender: 52.5% M

Shi et al. (2013)17

Lou et al. (2012)19

Cluster RCT Intervention: 24 wks; initial individualized dietary counseling followed by monthly reinforcement sessions (30 min) with registered dietitian. FU: None Setting: 5 HD units

RCT Intervention: 16 wks; monthly individualized consultations with research renal pharmacist and dietitian. FU: None Setting: HD and satellite units (education during HD session)

Cluster RCT Intervention: 8 wks; 2 weekly individual 20-min educational sessions with research renal dietitian. FU: None Setting: 1 HD unit (sessions)

I (n = 41), C (n = 40) Age in yrs ± SD: I: 50.36 ± 2.84 C: 59.63 ± 2.89 Gender: 48.5% M

Karavetian & Ghaddar (2013)16

Yokum et al. (2008)18

Quasi-experimental Intervention: 24 wks; monthly 20- to 30-min individualized education by research renal dietitian. FU: None Setting: 3 HD units (education during HD session)

I: Instructions on low P and P/protein ratio menus adapted to the patient’s dialysis shift and to Mediterranean diet characteristics, with indications about the quantities of food and preparation methods C: Received usual dietary recommendations. Theory: None

C: Patients managed without a decision tree, educated only by the dietitian. Theory: None

I: Management according to a defined P management protocol decision tree

I: Individualized counseling, interactive educational games, and discussion, in addition to individual laboratory results review and relevant nutritional counseling if required. All education was summarized into handouts and given to patients. Posters of high- and low-P food items were posted in the HD waiting room, and small booklets of high-P food items and their low-P alternatives were available C: No nutritional intervention. Theory: Self-management dietary counseling positive reinforcement (self-regulatory theory) I: Use of educational booklet; dialogue with participants or their relatives who were invited to the session; and 1 PowerPoint lecture (including colorful pictures of high-P foods) about general P knowledge and P binders, method to maintain P balance C: Standard medical and social care, but no educational materials. Theory: None

I: Education aimed to empower patients for self-evaluation and self-regulation, to control dietary P (prevention of renal bone disease; avoidance of high-P foods; medications), using educational posters, handouts, puzzles, and an individualized P tracking tool and laboratory results review. Dietitians demonstrated preparation of renal-healthy meals. C: Routine care that included laboratory results review with the same dietitian. Theory: None

I: Education aimed to empower patients to get involved in their healthcare, using educational colorful booklet with cartoon models explaining importance of lifestyle change and health, dietary restriction, medication, and relevant blood tests, plus a medication record chart and a refrigerator magnet (used as a reminder). C: Provided with medication record chart only. Theory: None

RCT Intervention: 1 time; 40-min individualized education by renal dietitian. FU: At wk 12 post intervention. Setting: 1 HD unit (education just before HD session)

I (n = 32), C (n = 31), both hyperphosphatemics; Age in yrs: range 18–76+ Gender: I: 34.37% M C: 41.93% M

Educational technique

Design

Ford et al. (2004)15

Reference Sample Studies in descending order of effect size I (n = 29), C (n = 29), both Ashurst Ide & hyperphosphatemics; Dobbie Age in yrs: (2003)14 I: 54.2; range 22–77 C: 53; range 23–88 Gender: I: 66% M C: 56% M

I: ↓ sig.[P]: Pre: 7.1 ± 1.5 mg/dL Post: 5.5 ± 1.4 mg/dL C: ↓ NS [P]: Pre: 6.8 ± 0.8 mg/dL Post: 6.2 ± 1.3 mg/dL

I: ↓ NS. [P]: Pre: 6.29 ± 0.86 mg/dL Post: 5.61 ± 1.67 mg/dL C: ↑ sig. [P]: Pre: 5.82 ± 0.99 mg/dL Post: 6.41 ± 0.77 mg/dL

C: ↑ NS [P]: Pre: 6.16 ± 1.34 mg/dL Post: 6.51 ± 1.36 mg/dL I: ↓ sig. [P]: Pre: 6.66 ± 1.17 mg/dL Post: 5.51 ± 1.20 mg/dL C: ↓ NS [P]: Pre: 6.51 ± 1.45 mg/dL Post: 6.38 ± 1.48 mg/dL

C: ↓ NS [P]: Pre: 7.2 ± 1.3 mg/dL Post: 6.7 ± 1.7 mg/dL I: ↓ sig [P]: Pre: 6.55 ± 1.89 mg/dL Post: 5.39 ± 1.97 mg/dL

C: ↓ NS [P]: Pre: 6.13 ± 0.15 mg/dL Post: 5.92 ± 0.12 mg/dL (data extracted from graph) Results sustained over 3 mo I: ↓ sig. [P]: Pre: 6.8 ± 0.72 mg/dL Post: 5.2 ± 1.2 mg/dL

I: ↓ sig. [P]: Pre: 6.07 ± 0.01 mg/dL Post: 4.96 ± 0.12 mg/dL

Results

Table 1 Main characteristics of reviewed articles with studies ordered in descending order of effect size, when available (upper portion), and year of publication, when effect size was not available (lower portion).

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I (n = 145), C (n = 134), both hyperphosphatemics; Age in yrs ± SD: I: 54 ± 13 C: 52 ± 13 Gender: I: 57% M C: 66% M

I (n = 34), C (n = 33), both hyperphosphatemics; Age in yrs ± SD: I: 60.4 ± 15.6 C: 54.9 ± 15.9 Gender: I: 73.5% M C: 52.5% M Io (n = 32), Iv (n = 31) Io & Iv age in yrs ± SD: 38.5 ± 9.5 Io & Iv gender: 52.4% M

Sullivan et al. (2009)21

Morey et al. (2008)22

Reddy et al. (2009)25

n = 115 Age in yrs: 61.1 Gender: 54.8% M

Studies without effect sizes by year of publication n = 702 Mayne et al. Age in yrs ± SD: (2012)24 61 ± 15 Gender: 56% M

Baraz et al. (2010)23

I (n = 16), C (n = 17), both hyperphosphatemics; Age in yrs ± SD : 52.5 ± 14.2 Gender: I: 62.50% M C: 47.05% M

de Araujo et al. (2010)20

Prospective, multicenter, single-arm trial – no control Intervention: 24 wks; a 1-time individualized dietary education session with renal dietitian and individualized regular monitoring for [P] by facility staff. In addition, 5 different educational materials that were mailed to patients during the course of the study. FU: None Setting: 8 HD units No control trial Duration: unclear; group (n = 6–8) education by research dietitian. FU: None Setting: 2 satellite HD units (education during HD session)

Randomized trial – no control Intervention: 2 times; 30-min education by expert renal nurse. FU: At wk 8 post intervention Setting: 3 HD units

RCT Intervention: 24 wks; individualized monthly education by study dietitian. FU: At wk 24 post intervention Setting: N/A (education during HD session)

RCT Intervention: 6 times; 30-min group education (type of educator & intervention duration: unclear). FU: At wk 13 post intervention Setting: 2 HD units (education immediately before HD session) RCT Intervention: 8 wks; a 30-min one-time individualized education and a reinforcement session by telephone at FU with study coordinator (dietitian). FU: At wk 4 post intervention Setting: 14 HD units (education during HD session)

Use of booklets written by a dietitian, along with an audio cassette on all relevant information, translated into local language. Theory: None

Five communications were mailed to patients, addressing portion size, following a renal-healthy diet at home and while eating out, function of different members of the renal-care team, simple but specific ways to involve patients and caregivers in the patient’s care. In-center education focused on diet, P management, and support for adherence to P binder treatment. Theory: None

Iv: Individual video education during HD sessions. Both educations included information on dietary management, restricted/nonrestricted foods, reasons for compliance, and possible consequences of noncompliance. Theory: None

Io: Didactic and interactive oral group sessions the day after HD session. A teaching booklet was also provided

C: Standard care with in-service dietetic consultations at baseline and mo 6. Theory: Motivational counseling, negotiation, behavior modification therapy, reminders, reinforcement, supportive care

I: Teaching patients to read food labels . Use of handouts on avoiding foods with P additives and consequences for health. Patients were provided with menus of restaurants they usually visit, and the high- and low-P meals were marked to help patients with food selection. Reinforcement session conducted via telephone. Material was prepared by dietitians C: Study coordinator telephoned patients at FU and inquired on how often they read nutrition facts labels, eat at fast-food restaurants, and receive P-related recommendations from their facility dietitian, without providing education or feedback. Theory: None I: Advanced dietetic verbal and written counseling aimed at limiting dietary P and improving compliance with P-binder treatment

I: Education on avoiding food rich in P, the correct use of binders, the importance of biochemical parameters, and manifestations of bone diseases using visual educational tools (images, drawings, etc.), anatomic models, and simulator mannequins C: Information on vascular access, types of catheters, and arteriovenous graft. Theory: None

↓ sig. [P]: only among the hyperphosphatemics (n = 30): Pre: 6.35 ± 0.12 mg/dL Post: 5.95 ± 0.24 mg/dL

↑ sig. percentage of patients achieving [P]