41

Pain, 50 (1992) 41-50 0 1992 Elsevier Science Publishers B.V. All rights reserved 03~-3959/92/$05.00

PAIN 02069

Follow-up results from a randomised controlled trial evaluating in- and outpatient pain management programmes Janet Peters a Department

a, Robert

G. Large a,b and Gail Elkind

a

of Psychiatry and Behavioural Science, University of Auckland, and ’ Pain C&r&, Auckland Hospital, Auckland (New Zealand)

(Received 23 February 1990, revision received 31 January 1992, accepted 31 January 1992)

This study reports a 9-18 month follow-up of a randomised controlled trial of pain management Summary programmes for chronic, non-malignant pain, Twenty-two inpatients, 18 outpatients and 12 control subjects completed the follow-up assessments. Significant treatment effects were demonstrated by the inpatient group on pain ratings, the Pain Behaviour Checklist, and General Health Questionnaire, with similar effects demonstrated by the outpatient group on the former 2 measures. The findings were confounded by higher inpatient scores at pretreatment, in comparison with the 2 other conditions. There was a high drop-out rate of subjects, particularly from the control condition which illustrates the limitations of controlled group designs in this area. Analgesic use, activity levels and pain ratings were also evaluated using the criteria for ‘success’ described by Malec et al. (1981). Results indicated that 68% of inpatients, 61% of outpatients and 21% of control subjects met all 3 criteria. Both treatment programmes were effective in returning patients to paid employment, whilst 3 control group patients gave up work. The cost-benefit implications of these changes are discussed. We conclude that pain management programmes contribute substantially to the rehabilitation of chronic pain sufferers. Key words: Chronic non-malignant

pain; Treatment

evaluation; Pain management;

Introduction A critical issue in the treatment of chronic, nonmalignant pain is the maintenance of treatment gains. Evaluations of both in- and outpatient pain management programmes have demonstrated increased levels of activity and/or exercise, decreased use of medication, and moderate reductions in self-report of pain intensity in the short term (Linton 1986). However, the long-term efficacy of the multidisciplina~ pain management approach has yet to be substantiated. This issue is particularly important in view of the chronicity of the intractable pain problem and in view of the fact that programmes do not offer a ‘cure’; rather, mainte-

Correspondence to: Dr. R.G. Large, Department of Psychiatry and Behavioural Science, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand.

Controlled trial; Cost benefit

nance of treatment gains may be seen as the long-term continuation of the skills, techniques and behaviour changes learnt or made whilst in treatment (Lutz et al. 1983). Thus it is the reduction in disability, rather than pain per se, that is the primary goal (Sturgis et ai. 1984; Fordyce et al. 1985). Comparisons among evaluative studies are difficult to make for several reasons. First, a continuum exists in the treatment outcome literature, ranging from those studies which do not report any follow-up data (Cairns and Pasino 1977) to those that report follow-up questionnaire data for up to 8 years (Roberts and Reinhardt 1980). Second, criteria for acceptance into a programme differ widely, thus ultimately affecting treatment outcome. Again, a continuum exists from those studies which do not specify criteria for acceptance (Herman and Baptiste 1981) through to those which describe such stringent criteria (Tyre and Anderson 1981) that one doubts the generalizability of the findings. Furthermore, economic considerations also enter into the equation, with several

42

studies allowing entry for only those patients with insurance coverage (Sturgis. et al 1984; Mayer et al. 1986). Third, the variables being measured vary considerably among studies. On the one hand, several studies report assessment of a relatively narrow set of variables: for example, subjective tension, EMG activity and pain ratings (Keefe et al. 1981). In contrast, others such as Roberts and Reinhardt (1980) attempt to measure a broader range of parameters encompassing vocational, recreational and social functioning. The distinction between the narrow versus broad assessment style is an important one, with the former more in keeping with a narrow biomedical model and the latter well suited to the biopsychosocial model (Roy 1984). Fourth, criteria for success or improvement have not yet been clearly delineated. Descriptions of successful outcome may also be viewed on a continuum, from one report merely stating that patients were leading ‘normal lives’ at follow-up (Anderson et al. 1987) through to more stringent operational definitions including criteria for employment/activity and exercise status, medication intake and self-report of pain (Roberts and Reinhardt 1980; Malec et al. 1981). A method of determining overall success was described by Malec et al. (1981). These authors employed the equation, with specific criteria outlined for each of the 3 categories comprising success: ‘Success’ = ‘Drug-free’ + ‘Active’ + ‘Managed Pain’. We have previously reported the pre- and posttreatment results of a randomised controlled group evaluation of the in- and outpatient pain management programmes at Auckland Hospital, including a detailed description of the research methodology, treatment and measures used (Peters and Large 1990). Results may be briefly summarised as follows. First, at pretreatment, inpatients showed more subjective distress than those in the other 2 groups. Second, compared to the control condition, patients in the treatment groups demonstrated significant improvement on measures of psychological distress (General Health Questionnaire: GHQ), health-related impairment (Sickness Impact Profile: SIP) and pain intensity (VAS O-10) following physical exertion (a stair climbing test). Third, significant treatment effects were not found on measures of depression (Beck Depression Inventory: BDI), areas of body pain (patient’s and physiotherapist’s Pain Drawing: PD), numbers of stairs climbed, and range of movement (assessed by a physiotherapist). Practical difficulties encountered in the study in terms of measures and research design were outlined and will be further highlighted in the present article. This paper reports the follow-up results of this randomised controlled trial. In addition, using the equation developed by Malec et al. (19811, we have determined the overall success of the treatment programmes versus the control condition.

Methods Subjects Criteria for acceptance into this study were: chronic non-malignant pain of more than 6 months duration and no psychotic illness; all appropriate medical or surgical investigations and/or treatments were completed. As reported previously, of 132 patients referred to the study, 85 initially provided consent and were randomly assigned to 1 of 3 groups as follows: inpatient (IPMP)= 33. outpatient (OPMP) = 29, and control (Cl = 23. Randomisation was determined by a throw of dice with no manipulations made to balance sample size in each group. The distribution, although uneven, is well within the bounds of chance (x = 2.69, P > 0.25). Seventeen patients dropped out before the post-treatment assessment: 4 IPMP, 6 OPMP, and 7 C subjects. Proportionately more patients dropped out of the control group, followed by the outpatient and then the inpatient groups. Pre- and post-treatment results were therefore available for 29 IPMP, 23 OPMP, and I6 C subjects. It was not possible to ascertain reasons for dropping out in all cases, but a common reason was dissatisfaction with the group assigned; this accounted for 3 of the drop-outs from the control group. Despite the large number of drop-outs, there were no statistically significant differences between groups on demographic or clinical variables. Married European women predominated in the sample (26 men, 42 women). The mean age was 43.9 years, duration of pain was fairly equally distributed among the categories ( > 6 < 12 months to > 20 years), with the most common sites of pain being low back and head. During the follow-up phase of the research, a further 16 patients withdrew from the study: 7 IPMP, 5 OPMP and 4 C subjects. Thus, follow-up data were obtained for 22 IPMP, 18 OPMP, and 12 C subjects. It was not possible to elicit reasons from all patients who dropped out nor was it possible to gauge their current pain experience or adaptation accurately. We were constrained by practical difficulties in gaining this information as well as by considerations for patients’ autonomy and privacy when they indicated unwillingness to be further involved. Although the data we could glean did not lend itself to statistical analysis, it appeared that, in all 3 groups, these patients dropped out as frequently when they were functioning well as when they were functioning poorly. Typical reasons ranged from ‘working full-time and too busy to come in’ to ‘in too much pain’ to undertake follow-up.

Assessment Follow-up was initially undertaken with patients attending appointments at Auckland Hospital for the purposes of individual assessment (by researcher and physiotherapist). However, many patients reported being unable (because of economic considerations, work or family commitments) to attend these sessions. Thus individual questionnaire data were obtained by post, and 4 measures were discontinued (making videos of patient’s sitting, walking, standing, bending behaviours; physiotherapist’s assessment of range of movement; physiotherapist’s PD and stair climbing test). It was not possible for the evaluators to be blind with respect to subjects’ group assignations. The physiotherapist assessments are not included in the results reported here. All of the data reported were collected by a researcher f.I.P.1 and research assistant who were not involved in the clinical management of patients. Follow-up assessments ranged from 9 to 18 months post-treatment and were equally distributed amongst the 3 groups with most follow-ups occurring at the 12 month mark. All patients were posted a brief summary of the research, that is, their own results and the overall findings upon completion of the project.

Inpatient pain management programme Described in detail elsewhere (Peters was cognitive-behavioural in orientation

and Large 1990) treatment and was conducted in a

43 general medical ward by a multidisciplinary team under the direction of R.G.L. The basic components of the programme were: education on the nature of pain, relaxation and allied techniques including EMG-feedback, cognitive restructuring and visualisation, structured exercise and physical activation, counselling, medication management and withdrawal, where appropriate, and staff reinforcement of activity and well behavioprs. Six patients participated as a cohort over a 4 week period. All patients stayed in hospital Sunday to Friday whilst the weekends were used for trying out new-found knowledge and techniques in vivo.

Outpatient pain management programme Primarily cognitive-behavioural in orientation, this treatment programme was conducted by a multidisciplinary team during 9 weekly, 2 h sessions at the hospital. A maximum of 10 patients participated, and the content was similar to the inpatient programme. More emphasis was placed on homework with patients being encouraged to work on an activity programme and relaxation practice each day. There was less opportunity for individual counselling and more emphasis on education.

Control group Patients in this group had been informed that they would be assessed 4 times in 1 year, were able to receive standard medical treatment through the Outpatient Pain Clinic if required, but would be unable to participate in an in- or outpatient pain management programme until the completion of the follow-up period. In this sense they were not a waiting list sample as no undertaking was given that they would be called up to attend a pain management programme in the future, only that they could be considered for a programme, if they wished, at the completion of the study.

Results Self-report measures Pain ratings &AS).

Fig. 1 shows patients’ ratings of pain intensity over the past week (N = 42). A significant time x treatment interaction was demonstrated (F (4, 78) = 3.56, P < 0.05). Although scores from all 3 groups decreased slightly at post-treatment, scores from the treatment groups decreased further at follow-up (IPMP x = 4.05; OPMP x = 4.40), in contrast to the higher follow-up scores from the control group (x = 6.25). Pain Behaviour Checklist (PBC). Fig. 2 (N = 47) shows a significant time x treatment interaction was found (F (4, 88) = 3.90, P < 0.01). Both treatment groups reported engaging in less pain behaviour at follow-up, when compared with pre- and post-treatment scores. The scores from the control group remained relatively constant, suggesting that little change had occurred. At pretreatment a Tukey test associated with the ANOVA showed that inpatient scores were significantly higher than control scores (P < .05) whilst no significant differences are shown at follow-up. These results suggest a regression to the mean for the treatment groups from high pre-treatment scores to scores similar to those of the controls.

Outcome measures Self-report measures. Measures included the Beck Depression Inventory (BDI) (Beck et al. 1961), the McGill Pain Questionnaire (MPQ) (Melzack 1975), the Sickness Impact Profile (SIP) (Bergner et al. 19811, the General Health Questionnaire (GHQ) (Goldberg and Blackwell 1970), the Pain Behaviour Checklist (PBC) (Philips and Jahanshahi 19861, and a Pain Drawing (PD) (Margolis et al. 1986). Average pain intensity in the last week was.assessed using a 10 cm visual analogue scale WAS) (Scott and Huskisson 1976) in which 0 = ‘no pain’ and 10 = ‘unbearable pain’ with numeric anchors between these 2 endpoints. Medication. Data on medication intake were obtained from pa-

tient questionnaires, interviews and/or telephone practitioner questionnaires and hospital records.

contact, general

Vocational and benefit status/ recreational activities. Data on and Accident Compensation and Department of Social Welfare records. Costs of treatments. Data on costs of treatments were also ob-

these were obtained from the above sources

tained from the above sources. Statistical methods Each of the outcome measures was entered in a 3 X 3 (treatment X assessment period) repeated measures analysis of variance (ANOVA) using the General Linear Models Procedure in SAS. This procedure allows us to examine the change in each dependent measure by time (pretreatment, post-treatment and follow-up) which is a within-subjects effect, as well as the effects of treatment group and the interaction of time and treatment group. As data were missing from some patients, N varies from measure to measure; however, the SAS package used allowed for such omissions in analyses. Tukey’s test was used to compare each pair of means at each time for all measures tested. Only those comparisons which were significant at P < 0.05 are reported below.

Pre-treatment Fig.

Posttreatment

Follow-up

1. Mean VAS scores at pre-treatment, post-treatment follow-up for inpatient, outpatient and control groups.

and

44 20

15

24

\

pygq

10

22 5 20 L 18 C

I

1

Pre-treatment

Pre-treatment

Posttreatment

Follow-up

,

I

Posttreatment

Follow-up

Fig. 3. Mean scores on the General Health Questionnaire (GHQ) at pre-treatment, post-treatment and follow-up for inpatient, outpatient and control groups.

Fig. 2. Mean scores on the Pain Behaviour Checklist (PBC) at pre-treatment, post-treatment and follow-up for inpatient, outpatient and control groups.

General Health Questionnaire (GHQ). Fig. 3 (N = 46) displays the significant time x group interaction (F (4, 86) = 3.89, P < 0.01). Inpatient and control group scores decreased from post-treatment to follow-up whilst the outpatient scores increased. Inpatient scores were significantly higher than those for outpatients at pre-treatment (P < 0.05) on Tukeys test. Sickness ~~~~ct Profi‘le (SIP). At pretreatment, high inpatient scores were reflected in the significant differ-

ence (P < 0.05) between the inpatient group (x = 210.32) and the outpatient group (x = 123.15) on Tukey’s test. There was no significant time X group interaction CN = 40). Beck Depression Inventory (BDZ). At pretreatment Tukey’s test showed a significant difference between inpatient and outpatient and between inpatient and control groups (P < 0.05) with the inpatient scores reflecting higher ratings of depression (x = 20.18) than for the other 2 groups (OPMP x = 12.61; C x = 12.27).

TABLE I PERCENTAGE

OF PATIENTS ‘USING MEDICATIONS APPROPRIATELY’

Medication ’

AT PRE-TREATMENT Follow-up

Pretreatment IPMP (N = 22)

AND FOLLOW-UP

OPMP (N = 18)

C (N = 12)

IPMP (N = 22)

OPMC (N = 18)

c (N = 12)

Strong opioids Mild opioids Other analgesics Muscle relaxants and tranquifisers Antidepressants Nil

2 5 11 9 11 4

3 3 6 2 8 4

0 6 5 0 9 2

0 3 10 2 5 9

3 4 0 6 4

1 7 4 2 9 0

Total N Total not using medications appropriately Total (“loage) using medications appropriateIy

22

18

12

22

18

12

11

5

0

2

1

3

11(50%)

13 172%)

12 (100%)

’ Several patients were taking more than one type of drug; therefore, totals > N.

20 (90%)

1

17 (94%)

9 (75%)

45 TABLE II PERCENTAGE OF PATIENTS MEETING CRITERIA FOR ‘SUCCESS’ IN THE ‘ACTIVE’ CATEGORY AND BENEFICIARY FOR NON-ACTIVE PATIENTS AT PRETREATMENT AND FOLLOW-UP Pretreatment

Activity

Follow-up

IPMP (N = 22)

OPMP (N = 18)

C (N = 121

IPMP (N = 22)

OPMP (N = 181

C (N = 12)

Employed Training Home manager SO-100% exercises and increased recreation

3 0 1

2 0 3

4 0 4

10 1 5

5 2 3

1 0 4

0

0

0

2

2

0

Total

4 (18%)

5 (28%)

8 (67%)

Non-active Accident compensation Unemployment benefit Sickness benefit Invalids benefit Health insurance Unable to manage at home

7 2 3 0 0 6

5 1 4 1 1 1

1 0 2 0 0 1

0 1 0 1 0 2

2 0 3 0 1 0

1 1 5 0 0 0

4 (33%)

4 (18%)

6 (33%)

7 (58%)

18 (82%)

Total

13 (67%)

There was no significant time X group interaction (N = 51). The repeated measures ANOVA produced no significant findings on the MPQ or PD. Summary of self-report measures. For the SIP, BDI, MPQ and PDs, there were no treatment-related changes. In the cases of the PBC and GHQ, although treatment effects were shown, there were higher pretreatment scores for the inpatients which reduced to levels similar to those of the control group at follow-up. This may suggest a regression to the mean. In contrast the VAS ratings of pain intensity over the past week

12 (67%)

18 (82%)

S (42%)

show a significant time X treatment interaction, with treatment groups producing lower pain ratings at follow-up. Medication

Table I shows the intake of medication using the categories outlined by Malec et al. (1981) across the 3 groups at pretreatment and follow-up. Several patients were ingesting more than one type of drug, with few using strong opiods. Employing the criteria of Malec et al. (1981) for ‘drug-free’ which we have re-labelled

TABLE III A: PERCENTAGE

OF PATIENTS MEETING OVERALL CRITERIA FOR ‘SUCCESS’ AT FOLLOW-UP

Not using medications appropriately Not ‘Active’ Pain increased Pain + not ‘Active’ Pain + not ‘Active’ + not using medication appropriately Not ‘Active’+ not using medication appropriately Pain + not using medication appropriately Success = ‘using meds. appropriately’+ ‘active’ + ‘no pain increase’

B: COMPARISON

OF ‘SUCCESSFUL’ VERSUS NON-SUCCESSFUL

IPMP (N = 22)

OPMP (N = 18)

C (N = 12)

-1 -2 -2 -1 -1 0 0 1.5(68%)

-1 -6 0 0 0 0 0 11 (61%)

-5 -1 0 0 -2 -1 3 (25%)

PATIENTS IN THE 3 GROUPS AT FOLLOW-UP

IPMP

OPMP

‘Success’ on al1 3 criteria * Not successful on one or more criterion

15 7

11 7

3 9

29 23

Total

22

18

12

52

* P 0.025.

STATUS

C

Total

46

‘using medications appropriately’ (i.e., no use of strong opioids, muscle relaxants or tranquilisers at a follow-up of at least 6 months), the data demonstrate high percentages of patients meeting these criteria (IPMP = 91%, OPMP = 94%, C = 75%). Vocational status /activity

Table II shows patients’ activity and benefit status across the 3 conditions at pretreatment and follow-up. The categories described by Malec et al. (1981) were employed, that is ‘active’ indicates that, at a follow-up of at least 6 months, the patient met 1 of 2 criteria: (1) employed full- or part-time, in vocational training, or running a household, or (2) continuing 50-100% of the exercise programme with a reported increase in recreational activities. Additionally, a further analysis of patients beneficiary status was undertaken. It can be seen that more patients in the 2 treatment groups met the criteria for being active at follow-up, with inpatients showing the highest rate of activity (82%). In comparison, those in the control group were less likely to be successfully engaging in these activities at followup (42%) with a consequent increase in beneficiaries. Pain

As data from the VAS were incomplete for 9 subjects, similar ratings from the MPQ were substituted to allow pretreatment and follow-up comparisons. Malec et al. (1981) regarded patients as having ‘managed’ their pain if they reported no increase or less pain at follow-up of more than 6 months. Eighteen of 22 inpatients, all of 18 outpatients and 10 of 12 controls had no increase in average pain scores over the past week. Overall success

Table IIIa shows the data fitted to the equation of Malec et al. (1981) determining overall ‘success’. Deducting those patients who did not meet the criteria for ‘using medications appropriately’ and/or ‘active’ and/or ‘no pain increase’, the data indicate that 68% of inpatients, 61% of outpatients, and 25% of control subjects met all 3 criteria for success. Table IIIb shows the comparison between successful versus non-successful patients across the 3 conditions at follow-up. There is a significant difference between groups using chisquare in the number of treated patients meeting the success criteria at follow-up (x = 6.196, df = 2, P < 0.025), as compared to the control condition.

Discussion

This paper is a follow-up report on a randomised controlled trial of pain management for chronic nonmalignant pain. The results of the follow-up analyses

provide support for the efficacy of in- and outpatient pain management programmes at 9-18 month followup. Patients’ ratings of average pain intensity were significantly reduced at follow-up in the treatment groups compared with the control group. Measures of psychological distress and pain behaviour produced more equivocal results since the pre-treatment scores for inpatients were elevated compared with the controls. Thus, the treatment effects shown by these measures may be explained as a regression to the mean. Significant treatment effects were not found on the remaining self-report measures. The pre-treatment differences in measures such as the GHQ, BDI, PBC and SIP could point to a failure of proper randomisation. This is further supported by the control group showing less medication use and greater activity levels than the inpatients at pre-treatment. On the other hand, randomisation was procedurally correct, there were no demographic differences between groups and there were no pre-treatment differences in the VAS pain ratings, MPQ or PD. Because the self-report measures of psychological distress and illness were elevated, and more extreme in the inpatients, we postulate that this was due to some effect on the patients of being included in a treatment programme. We suggest that the inpatients were likely to rate themselves as more distressed on admission, as a consequence of being hospitalised and thus being more focussed on their symptoms. The patients included in the treatment programmes had further clinical interviews as part of the normal admission procedure. We suggest that this process may have highlighted psychological and illness aspects of the patients’ experiences and made these more salient and accessible to them. This may explain why pain measures were not elevated in the treatment groups, their pain being an accepted ‘given’ which all subjects inducted into the study had in common and which had already been acknowledged and accepted by the clinic. Thus, our view is that failure of randomisation is a possible explanation for the pre-treatment differences we have shown. It may be, however, that these differences are an effect of entry into a treatment group. We regret now that we did not introduce our pre-treatment measures prior to randomisation and suggest that future studies should take this into account. The operational criteria of Malec et al. (1981) may seem somewhat arbitrary, but they do provide a stringent test of ‘success’ which can be quantified. Above all they are operational criteria that allow comparisons to be made between studies. We have, however, altered the terminology. For example, ‘drug free’ is not really drug free but implies the use of appropriate medications in appropriate dosages. This is hazardous territory given current controversies on the use of opiates in chronic non-malignant pain and it may be

47

that our notions of what is appropriate in the pharmacotherapy of pain will change in time. At present, however, we take the view that strong opioids, muscle relaxants and tranquilisers are not usually appropriate for the majority of people suffering chronic pain. By the same token we are aware that a small dosage of a strong opioid may be preferable to large doses of a mild opioid. No patient was rated as ‘using medications approprately’ if he or she was taking more than 8 Di-Gesic (50 mg dextropropoxyphene napsylate, 325 mg paracetamol/tablet) daily or more than 8 Panadeine (8 mg codeine phosphate, 500 mg paracetamol/tablet) daily. These were, in fact, the only mild opioids used by the patients studied. Similarly, rather than use the term ‘managed pain’ we have substituted ‘no pain increase’ as a more descriptive term which does not imply any value judgements. The term ‘managed pain’ is not ideal in describing patients whose pain levels have remained static or reduced, since variables other than coping may be relevant to changes in pain intensity. Nevertheless, we feel it is important to include this dimension, as a potential criticism of pain management approaches is that patients are simply coerced into attitudes of stoicism, despite continued pain. Including this criterion ensures that patients who may be funtionally improved, at the expense of increased pain, are not included as ‘successes’ in data analysis. As it happens, the majority of patients met this criterion, including the controls, and this does challenge its utility. It is clear that, in terms of these criteria, the inpatient programme evaluated in this study had a powerful effect on the overall functioning of patients. Malec et al. (1981) considered their 37% success rate for programme graduates as respectable, in view of the chronicity of patients’ pain problems. Thus, in the present study, the 68% and 61% success rate (for inand outpatient groups, respectively) demonstrate substantial continued improvement at follow-up. The outpatient programme appears to have been less successful in achieving functional change in patients (82% of inpatients met the ‘active’ criterion at follow-up compared with 67% of outpatients) but produced similar reductions in pain ratings. It has been difficult to get precise figures from the Auckland Area Health Board on the costs of these programmes. We estimate that the inpatient programme costs NZ$7000/patient and the outpatient programme NZ$lOOO/patient. In New Zealand these costs are borne by the state, and the programmes were free to the patients at the time of the study. An analysis of the inpatient programme for the study period gives a cost of NZ$154,000 for treating 18 patients who completed the follow-up. Six patients came off accident compensation benefits (average benefit = NZ$16,830/year in 1989) and 3 came off sick-

ness benefits (average benefit = NZ$10,400/year). This represents a saving to the state of NZ$132,180 over 12 months, if we calculate the costs of maintaining benefits for that period. Subtracting these savings from treatment costs leaves a shortfall of NZ$22,000. A similar analysis of the outpatient programme shows a cost of NZ$18,000 for treating 18 patients. Three patients came off accident compensation benefits and 1 came off sickness benefit. This represents a saving of NZ$60,590 over 12 months. Therefore the programme has saved the state NZ$42,590. Without taking changes in health care utilisation into account, these figures suggest that, in the long run, the pain management programmes are likely to save money for the state by returning people to active employment. The effect is most dramatic for the outpatient programme, but it should be remembered that benefits and dependency are long-term issues and that if the change in occupational status of these patients is maintained for as long as 5 years, then the savings to the state are NZ$660,900 and NZ$304,450 for the inpatient and outpatient programmes, respectively. Thus, although the inpatient programme is more costly, this study does suggest that it may be more cost effective if one takes the long-term view. It should also be borne in mind that, in the present study, patients with varying impairments and disability were randomly assigned to the treatment groups. Our data do not allow an analysis of the differential efficacy of the 2 programmes when levels of impairment and disability are taken into account. Further research is required to explore the possibility that a more intensive programme may be more cost effective for the more disabled patients. One cannot draw conclusions which are too strong from these data because of the small numbers and the relatively brief follow-up period. Nevertheless, this is a randomised controlled trial and an analysis of the control group’s outcome provides an interesting contrast to the treatment groups. There was no change in this group with regard to accident compensation benefits, but 3 patients went onto sickness benefits during the study period. Thus these patients represent an additional cost of NZ$31,200 to the state over 12 months. The indications are, therefore, that providing only standard medical treatment for patients with chronic pain may well lead to ongoing dependency upon state-provided benefits. Costs of medical investigations and treatments have been elusive because of the inadequate cost-accounting measures used by the state-funded hospital system in New Zealand. In the 12 months prior to the study the patients spent a total of NZ$10,820 in general practitioner visits and NZ$23,490 in other medical costs. Seventy-three percent had seen a physiotherapist, 46% an orthopaedic surgeon, 51% an anaesthetist, 50% a

4x

rheumatologist, 36% a neurologist, 21% a psychiatrist and 19% had had a CT scan. Whether the pain management programmes have been successful in reducing the extent of health care resource utilisation by these patients remains to be determined by further data collection and follow-up. This remains a crucial issue in determining the cost benefits of pain management. Although there is clearly need for caution in interpreting our rest&s, the data do suggest that pain management may reduce pain intensity, encourage appropriate use of medications, increase activity and return patients to paid employment. Furthermore, it would seem that this can be done without exacerbating patients’ pain experiences and that, when empIoyment status is taken into account, there may be substantial financial cost benefits to be gained. The present study highlights some of the methodological, theoretical and practical difficulties involved in clinical research. First, at the beginning of this research project, the use of a broad range of self-report, physiological, behaviouraf and social measures was envisaged. Unfortunately, during the process of the research, several measures were withdrawn because of practical difficulties, namely, problems with equipment reliability (EMG biofeedback), staffing constraints, and inability of patients to attend follow-up appointments. However, the results of the self-report questionnaire data provide an important comparison to the more objective data on medication use and vocational status. It would seem that the latter data provide a clearer picture of an individua~‘s day-to-day functioning, thus sole reliance on questionnaire data may be misleading. Second, the criteria for acceptance into the study were chronic non-malignant pain of more than 6 months duration, no psychotic illness, and completion of all appropriate medicat or surgical investigations and/or treatments, It appeared that the first 2 criteria were met through the careful medical and psychosocial assessments conducted by clinicians at the Pain Clinic. However, the 3rd criterion was found to be undermined in some instances in that several patients (after entry into the study) were followed up by other specialist clinics in the hospital and were re-investigated or offered additional treatments. Such occurrences may confound the present results and highlight the importance of communication between all health-care professionals involved in an individuai patients treatment. This problem appears to be common elsewhere. MaIec et al. (1981) found 38% of 26 programme graduates were hospitalised for pain after completing an inpatient pain management programme, despite medical histories suggesting an extremely low probability of success with such treatment. Third, contributing to the high success rate (when comparing the results to Malec et al. (1981), is the

smaller amount of medication (particularly narcotics and tranquilisers) used in the present study. Categorisation of different types of drugs is difficult, but we considered it useful to distinguish between: strong opioids (e.g., Temgesic/Buprenorphine, Palfium/Dextromoramide, Pethidine hydrochloride) and weak opiods (e.g., Di-Gesic/dextropropoxyphene napsylate plus paracetamol, Panadeine/codeine phosphate plus paracetamol), and other analgesics {e.g., Aspirin), rather than using the less informative narcotic/non-narcotic dichotomy. It appears there are major differences in the prescribing habits of doctors in NZ as compared to the USA. Several studies emanating from the USA describe high percentages of chronic patients using narcotics at pretreatment: for example, 73% of 40 patients (Malec et al. 1981) and 63% of 47 patients (Jacobs 1987). In contrast, in the present study, only 10% were using strong opioids at pretreatment. Furthermore, this low percentage is similarly reflected in the Pain CIinic at Auckland Hospital from whence the research subjects were referred. Current policy is for strong opioids to be prescribed for chronic non-malignant pain only as a last resort measure. Concern about the over-prescribing of strong opioids has led to a register of patients on such drugs being held at the Clinic, with periodic reviews of drug status. Fourth, as discussed in the earlier study, generalizability of findings is limited by the small sample. Eighty-five patients initially provided informed consent, with 17 (20%) dropping out before the post-treatment assessment. A further 16 (24%) dropped out during the follow-up period. We have too few data to make any judgements about the homogeneity of the drop-out group; as a consequence, the results of those who completed the study must be interpreted with caution. Uncontrolled studies have described a low percentage of responders to fohow-up assessment: e.g,, 2 studies (Gottlieb et ai. 1982; Lutz et al. 1983) averaged 55% responding at follow-up. In the present study the highest drop-out rate occurred at the control group (52%) which points to the difficulty of including a control group in clinical research. Fordyce et al. (1985) suggested that chronic pain patients are unlikely, without indications of progress, to maintain their status as a control subject throughout the treatment and follow-up of treated groups. The higher drop-out rate, as well as anecdotal information suggesting that several control subjects were engaging in ‘fringe’ therapies whilst in the study, provides evidence to support this contention. Furthermore, the study provides strong support for the widely held clinical belief that patients with chronic non-malignant pain do not have a high probability of spontaneous improvement, as indicated by the deterioration of the control group (Violon 1982). This deterioration, evidenced by increased pain ratings, increased medication use, decreased activity levels and

49

further utilisation of sickness benefits is of serious concern. It does raise the possibility that the control condition was actively harmful to the control subjects, a thought which creates further difficulties in interpreting our results. In fact, the drop-out rate is the largest single factor contributing to the caution with which these results must be interpreted. As far as we can tell there was no specific bias evident in the drop-outs except that subjects were more likely to drop out of the control group. As stated in the results section patients dropped out as much for positive reasons as for negative ones. Nevertheless, the fact remains that we have lost access to a substantial proportion of our original sample. In our view this calls into question the utility of the group control method in research on pain management. Any strategies which are usually suggested to improve subject retention run the risk of damaging either the study or the subjects. Inducements for subjects to remain in a control condition are likely to detract from the objectivity of the study, whilst more rigorous follow-up methods may run counter to the current respect we are developing for patient autonomy and choice. Nor is the waiting list solution a real solution, since it sets up expectancies which are likely to have patients suspend making decisions about benefits and treatments whilst they wait for the ‘definitive’ treatment. We consider that the time has come to weigh up the potential advantages that group controlled comparisons may have in, possibly, proving the benefit of pain management versus standard medical care, against the potential damage that may be done to subjects randomised into control conditions. Fifth, as maintenance of treatment depends on the continuation of skills learnt while in treatment, it would seem logical that gains could be improved by structuring periodic ‘relapse prevention’ or ‘booster’ sessions into follow-up services. This would enable patients to practise previously learnt skills and give them the opportunity to discuss current vocational or psychosocial difficulties.

Conclusion Whilst we have expressed many reservations about the interpretation of our study it nevertheless provides evidence that pain management programmes improve the overall functioning of chronic pain sufferers and that the more intensive the programme, the greater the improvement. This difference is especially likely to be shown in objective measures of functioning, such as activity and work status, rather than in self-report measures. In contrast patients who are left to rely on conventional medical support, languish or deteriorate. Placed in context with other research this study con-

tributes to the growing evidence that pain management programmes are the treatment of choice for patients disabled by chronic non-malagnant pain. Furthermore it would seem that these programmes are cost-effective in the long term, whilst the alternative of standard medical treatment may be more costly than is realised. It remains now for us to determine the precise cost benefits and optimum intensity of our programmes. Further definition of admission criteria and the effective components of a successful programme would also be of value.

Acknowledgements We thank Ms. Frances James for her practical and moral support and Ms. Rain Lamdin for her help in the statistical analyses. This research was supported by Grant No. 81187 from the Auckland Medical Research Foundation and was approved by the Auckland Hospital Research Ethics Committee.

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