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Randomised controlled trial of exercise for low back pain: clinical outcomes, costs, and preferences |
Moffett J K, Torgerson D, Bell-Syer S B, Jackson D, Llewlyn-Phillips H, Farrin A, Barber J |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology Exercise programme for low back pain. The programme comprised exercise classes of one hour each spread over four weeks. The classes were led by a physiotherapist and included strengthening exercises for all main muscle groups, stretching exercises, relaxation session and brief education on back care. A cognitive-behavioural approach was used.
Economic study type Cost-effectiveness analysis.
Study population Patients aged between 18 and 60, medically fit to undertake exercise, and suffering from mechanical low back pain of at least 4 weeks but less than six months duration.
Setting Community and primary care. The economic study was performed in York, UK.
Dates to which data relate The years during which data were collected for the effectiveness analysis and the year of the prices used were not stated.
Source of effectiveness data The evidence for final outcomes was derived from a single study.
Link between effectiveness and cost data Costing was undertaken prospectively on a subsample of the patients included in the effectiveness analysis: 70 patients from the intervention group and 74 from the control group.
Study sample Patients met the inclusion criteria by having mechanical low back pain of at least four weeks' duration but less than six months, aged between 18 and 60 years, declared medically fit by their GP to undertake the exercise and consulted one of the GPs participating in the study. Patients with any potentially serious pathology were excluded, as were any patients who would have been unable to attend or participate in the classes. Of the 187 patients included in the trial, 89 were randomised to the intervention and 98 to the control group. Power calculations were used to determine sample size but a smaller sample than was originally planned meant that the power to detect a 1.5 point difference was reduced to 72%. However, there was still 90% power to detect a 2 point difference in outcome.
Study design This was a randomised-controlled trial in which eighty-seven general practitioners agreed to participate; only one invited practice declined to participate. Single-handed practices were not invited. A pre-prepared randomisation list was generated from a random numbers table and participants were stratified by practice in blocks of six. The trial co-ordinator ensured concealment of allocation from the clinical researchers by providing the research physiotherapist with a sealed envelope for a named patient before baseline assessment. The follow up period was 1 year. The loss to follow up for the intervention and the control groups was as follows: at 6 weeks 4 patients in each group; at 6 months 12 in each group; at 1 year 6 in the intervention group versus 10 patients in the control group.
Analysis of effectiveness The analysis was based on intention to treat. The main outcome measures were the Roland back pain disability questionnaire, which measures functional limitations due to back pain, and the Aberdeen back pain scale, which is more a measure of clinical status. Assessment was carried out at the patients' general practice six weeks after randomisation to treatment. In addition, patients were asked to complete pain diaries in the week before their first assessment and in the week before their second assessment. Patients were also evaluated at 6 and 12 months' follow up by means of questionnaires, which they were asked to complete and return. The EuroQol health index and the Fear and avoidance beliefs questionnaire were also administered. The clinical and demographic characteristics of the patients in the 2 groups were fairly well balanced at randomisation, although those allocated to the intervention group tended to report more disability than did the control group.
Effectiveness results The effectiveness results were as follows:
After adjustment for baseline scores, the intervention group showed greater decreases in all measures of back pain and disability compared with the controls.
At six weeks after randomisation, patients in the intervention group reported less distressing pain than the control group (-10.2 versus -5.0; p=0.03) and a marginally significant difference on the Roland disability questionnaire scores (-2.86 versus -1.94). Other variables were not significantly different, but the differences in change were all in favour of the intervention group.
At six months the difference of the mean change scores of the Roland disability questionnaire was significant (intervention group -2.99, control group -1.64).
At one year the differences in changes of both the Roland disability questionnaire (intervention group -3.19, control group -1.77) and the Aberdeen back pain scale (intervention group -12.92, control group -8.48) were significant.
Most of the intervention group improved by at least three points on the Roland disability questionnaire: 53% (95% CI: 42% - 64%) had done so at six weeks, 60% (95% CI: 49% - 71%) at six months and 64% (95% CI: 54% - 74%) at one year.
In the control group the clinically important improvement was 31% (95% CI: 22% - 40%) at six weeks, 40% (95% CI: 29% - 50%) at six months, and 35% (95% CI: 25% - 45%) at one year.
Clinical conclusions The results support the hypothesis that a simple exercise class can lead to long term improvements for back pain sufferers.
Measure of benefits used in the economic analysis The authors did not introduce a summary measure of benefit and only separate outcomes were reported.
Direct costs Patients' use of healthcare services was assessed using a combination of retrospective questionnaires and prospective diary cards, which were returned at 6 and 12 months' follow up. The economic evaluation addressed costs to the National Health Service (NHS): exercise classes, fees for GPs, physiotherapist, chiropractor, orthopaedic surgeon, x-rays, hospital stay, and equipment. Costs and quantities were reported separately. Costs were not discounted because of the 1 year time frame of the analysis.
Statistical analysis of costs Student's t test and non-parametric "bootstrap" tests were used in the analysis of costs.
Indirect Costs The number of days which patients took off work were recorded and costed at 45 based on the GDP capita per head (1996).
Estimated benefits used in the economic analysis Cost results Patients in the intervention group tended to use fewer health care and other resources (mean cost: 360.15, SD=582.27) compared with those in the control group (mean cost: 508.43, SD=1108.79). However, the mean difference, totalling 148 per patient, was not significant: the 95% CI suggests there could have been a saving of as much as 442 per patient in the intervention group or an additional cost of up to 146. Patients in the control group took a total of 607 days off work (cost 27,315) during the 12 months after randomisation compared with 378 days taken off by the intervention group (cost 17,010).
Synthesis of costs and benefits Authors' conclusions The authors concluded that the exercise programme was more clinically effective than traditional GP management and was cost-effective.
CRD COMMENTARY - Selection of comparators The reason for the choice of comparator is clear, as it was the common practice in the authors' setting.
Validity of estimate of measure of benefit The estimate of the measure of benefit used in the economic analysis is likely to be internally valid because of the randomised design and the adjustments for confounding factors. Although it was stated that the analysis was based on intention to treat, patients whose data were not available at follow up were not included in the analysis.
Validity of estimate of costs Resource quantities were reported separately from prices and adequate details of the methods of quantity/cost estimation were given. It is not clear what price year the authors used.
Other issues The authors' conclusions were justified and appropriate comparisons were made with other studies. It would have been helpful had the dates of effectiveness and resource use data been provided.
Implications of the study According to the authors this type of exercise programme should be more widely available.
Source of funding Research funded by the Arthritis Research Campaign, the Northern and Yorkshire Regional Health Authority and the National Back Pain Association.
Bibliographic details Moffett J K, Torgerson D, Bell-Syer S B, Jackson D, Llewlyn-Phillips H, Farrin A, Barber J. Randomised controlled trial of exercise for low back pain: clinical outcomes, costs, and preferences. BMJ 1999; 319(7205): 279-283 Other publications of related interest Frost H, Lamb S, Klaber Moffett J, Fairbank J, Moser J. A fitness programme for patients with chronic low back pain: 2 year follow-up of a randomised controlled trial. Pain 1998;75:273-9.
Roland M, Morris R. A study of the natural causes of back pain. Part 1: development of a reliable and sensitive measure of disability in low-back pain. Spine 1983;8:141-4.
Ruta D, Garratt A, Wardlaw D, Russell I. Developing a valid and reliable measure of health outcome for patients with low back pain. Spine 1994;19:1887-96.
Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Costs and Cost Analysis; Exercise Therapy /economics /methods; Female; Humans; Low Back Pain /economics /rehabilitation; Male; Middle Aged; Patient Acceptance of Health Care; Patient Satisfaction; Treatment Outcome AccessionNumber 21999008230 Date bibliographic record published 31/10/2000 Date abstract record published 31/10/2000 |
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