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Cost-effectiveness of medical and chiropractic care for acute and chronic low back pain |
Haas M, Sharma R, Stano M |
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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 Two treatments for patients with acute and chronic low-back pain (LBP) were examined. Chiropractic care consisted of spinal manipulation, physical modalities, an exercise plan and self-care education. Medical care included prescription drugs, an exercise plan and self-care advice, with some patients being also referred for physical therapy. Chronic LBP was defined as an episode of at least 7 weeks' duration.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised patients with the primary complaint of acute or chronic LBP. The patients had to be at least 18 years old and ambulatory. Pain had to be of mechanical origin (i.e. not due to tumours, inflammatory disease, or organic referred pain). Patients were excluded if they were pregnant or had contraindications to spinal manipulation.
Setting The setting was primary and secondary care. The economic study was carried out in the USA.
Dates to which data relate The effectiveness and resource use data were gathered from 1994 to 1996. The price year was 1995.
Source of effectiveness data The effectiveness evidence was derived from a single study.
Link between effectiveness and cost data The costing was carried out prospectively on the same sample of patients as that included in the effectiveness study.
Study sample A sample of 2,780 patients was identified from the practices of 60 chiropractic doctors (CD) and 111 primary-care medical doctors (MD) in 51 CD and 14 general practice community clinics. Patients were excluded if they had received care from a provider of the same type as the enrolling clinician in the previous 6 weeks, or if they did not understand English. The patients were divided between chronic and acute LBP groups. Among patients with chronic LBP, there were 527 individuals (55.4% women) in the CD group and 310 (52.6% women) in the MD group. The mean ages of these patients were 42.2 (+/- 14.4) years (CD group) and 39.4 (+/- 12.7) years (MD group), respectively. Among patients with acute LBP, there were 1,328 individuals (47.7% women) in the CD group and 615 (46.7% women) in the MD group. The mean ages were 42.1 (+/- 12.9) years (CD group) and 38.5 (+/- 12.1) years (MD group), respectively
Study design This was a prospective, multi-centre, longitudinal, practice-based, non-randomised comparative study. With the exception of one medical clinic, which was located in Vancouver (Washington), all medical and chiropractic clinics were located in Oregon. The length of follow-up was one year, and the outcomes were assessed at baseline and at 3 and 12 months. The response rates for the clinical outcomes were 66% at 3 months and 62.6% at 12 months. These were uniform across the groups.
Analysis of effectiveness Only patients with complete follow-up data appear to have been included in the analysis of the clinical outcomes. The clinical outcomes used in the analysis were pain, disability, physical and mental health, and satisfaction. Clinical and satisfaction outcomes were evaluated on 100-point scales. Pain severity, a primary clinical outcome, was measured on a 100-mm visual analogue scale (VAS) that ranged from "no pain" (0) to "excruciating pain" (100). Functional disability was measured with the Revised Oswestry Disability Questionnaire, a 10-item, 100-point scale assessing pain and daily activities. A higher score indicated greater disability. Physical and mental health was evaluated with sub-scales of the Short Form (SF)-12 questionnaire. A 3-item depression questionnaire appended to the SF-12 was used to screen for major depression or dysthymia. Two questions measured trust of the provider types, and one question evaluated confidence in treatment success. These three were measured on 6-point Likert scales dichotomised for the analysis.
Patient data were obtained using self-administered questionnaires. Several differences between the MD and CD cohorts were statistically significant at baseline, although the authors stated that only a few of them were clinically relevant. For example, for chronic patients, MD patients had greater disability, poorer physical health, and a greater prevalence of pain radiating below the knee. Regression analyses were carried out to adjust clinical outcomes for baseline characteristics. Statistical significance was set at a p-value of p<0.01, and a clinically important difference between groups for the primary outcomes was set at 10 points.
Effectiveness results In the chronic LBP cohort, the adjusted mean difference between the CD and MD groups after one year (positive value represents outcome improvement for CD compared with MD) was:
for pain, 7.3 (+/- 2.1), (p=0.000);
for disability, 5.4 (+/- 1.7), (p=0.001);
for physical health, 3.0 (+/- 3.6), (p=0.396);
for mental health, 1.2 (+/- 3.7), (p=0.757); and
for satisfaction, 18.1 (+/- 4.9), (p=0.000).
In the acute LBP cohort, the adjusted mean difference between the CD and MD groups after one year (positive value represents outcome improvement for CD compared with MD) was:
for pain, 3.6 (+/- 1.3), (p=0.007);
for disability, 2.7 (+/- 1.1), (p=0.012);
for physical health, 9.2 (+/- 2.5), (p=0.000);
for mental health, 5.4 (+/- 2.5), (p=0.032); and
for satisfaction, 14.0 (+/- 3.1), (p=0.000).
Clinical conclusions The effectiveness analysis showed that acute and chronic chiropractic patients experienced statistically significant better outcomes in pain, functional disability and patient satisfaction; no significant difference was found for mental and physical health in chronic patients. Clinically relevant differences were found for patient satisfaction (using a 10-point difference as threshold for clinically relevant improvement).
Measure of benefits used in the economic analysis All clinical outcomes used in the effectiveness analysis were used as summary benefit measures in the economic evaluation. These included pain, disability, mental and physical health, and patient satisfaction.
Direct costs The perspective adopted in the study was unclear. However, the analysis took office-based costs (including X-ray and prescribed medication), the costs of advanced imaging, surgical consultation, and referral to physician therapists into consideration. The unit costs were not presented separately from the quantities of resources used. The costs came from Medicare/ChiroCode relative value units and Medicare conversion factors in order to use a standardised measure of costs. The resource use data were derived from the sample of patients included in the effectiveness analysis. Discounting was not relevant as the costs were incurred during a 12-month period. The price year was 1995.
Statistical analysis of costs A multiple regression model was used to adjust the total costs for baseline differences in clinical and economic data. Statistical tests were also carried out to test the significance of differences in the costs.
Indirect Costs The indirect costs were not considered in the cost analysis.
Sensitivity analysis Sensitivity analyses were not carried out.
Estimated benefits used in the economic analysis See the 'Effectiveness Results' section.
Cost results The adjusted mean difference in office costs between the CD and MD groups after one year was $158 (+/- 60) among patients with chronic LBP, (p=0.009) and $112 (+/- 38) among patients with acute LBP, (p=0.003).
However, the adjusted mean difference in total costs between the CD and MD groups after one year was $1 (+/- 80) among patients with chronic LBP and $43 (+/- 47) among patients with acute LBP.
Differences in the total costs did not reach statistical significance in chronic and acute patients.
Log-transformations of the costs confirmed the untransformed results.
Synthesis of costs and benefits Incremental cost-effectiveness ratios were calculated by dividing the difference in cost between CD and MD by the difference in each benefit measure over a one-year timeframe.
In the chronic cohort, the incremental cost per unit of improvement in the benefit measures ranged from $0 to $0.7 when the total costs were considered and from $8.7 to $136.4 when only office costs were considered.
In the acute cohort, the incremental cost per unit of improvement in the benefit measures ranged from $3.1 to $16.1 when the total costs were considered and from $8.0 to $41.7 when only office costs were included.
The lowest ratios were found when patient satisfaction was used as the benefit measure, while the highest values were obtained when mental health was used as the benefit measure. Similar results were found when differences in benefits found after 3 months were used instead of those found after one year.
Authors' conclusions Chiropractic care was relatively cost-effective in the treatment of chronic low-back pain (LBP). The results were less clear for acute patients, where only small improvements were found in clinical outcomes at additional, but not statistically significant, costs.
CRD COMMENTARY - Selection of comparators The selection of the comparators was appropriate as MD and CD represented two widely used treatment providers for patients with LBP. You should decide whether they are valid comparators in your own setting.
Validity of estimate of measure of effectiveness As the effectiveness analysis was based on a published prospective cohort study, limited information on the characteristics of that study was reported in the current economic paper. In general, the use of a cohort study is associated with the limitations typical of non-randomised and unmasked studies, and the potential impact of confounding factors and selection bias cannot be ruled out. However, the authors carried out a regression analysis with the intention of reducing the impact of confounding factors. Moreover, the multi-centre design and the large sample size enhance the internal validity of the analysis. Some details of the regression analysis were given.
Validity of estimate of measure of benefit The summary benefit measures were specific to the disease considered in the study, although it may be possible to compare some with the benefits of other health care interventions.
Validity of estimate of costs The cost analysis was presumably restricted to those costs relevant to the payer, although this was not explicitly stated. The unit costs and the quantities of resources used were not presented separately, and some costs were given as macro-categories. This reduces the possibility of replicating the analysis in other settings. The costs were estimated using a standardised approach, which should have ensured that the most appropriate types of costs were used. The price year was reported, which will facilitate reflation exercises in other time periods. The cost estimates were specific to the study setting and the use of alternative estimates was not investigated. The authors stated that their analysis highlights the importance of considering costs other than office costs in order to take all aspects of care into account. It was also noted that hospitalisation and surgical costs were not included in the analysis as these economic data were not available. Similarly, over-the-counter costs were not considered because they were difficult to estimate.
Other issues The authors reported the results from several studies and stated that their findings were consistent with the majority of studies. Some discrepancies, which probably arose from different methodological aspects, were observed. The authors stated that caution will be necessary when generalising the results of their study to other settings as chiropractic scope of practice varies depending on the country. The external validity of the study is low because sensitivity analyses were not carried out. The study referred to patients suffering from LBP and this was reflected in the authors' conclusions.
Implications of the study The study results suggested that chiropractic care may be at least as effective as traditional medical care for the treatment of patients with LBP. Under some circumstances, chiropractic care may be more effective, especially among chronic LBP patients.
Source of funding Supported by the Health Resources and Services Administration, Department of Health and Human Services, Rockland (MD), and the Foundation for Chiropractic Information and Research, Norwalk (IA), USA.
Bibliographic details Haas M, Sharma R, Stano M. Cost-effectiveness of medical and chiropractic care for acute and chronic low back pain. Journal of Manipulative and Physiological Therapeutics 2005; 28(8): 555-563 Other publications of related interest Haas M, Goldberg B, Aickin M, et al. A practice-based study of patients with acute and chronic low back pain attending primary care and chiropractic physicians: two-week to 48-month follow-up. J Manipulative Physiol Ther 2004;27:160-9.
Assendelft WJ, Morton SC, Yu EI, et al. Spinal manipulative therapy for low back pain. A metaanalysis of effectiveness relative to other therapies. Ann Intern Med 2003;138:871-81.
UK BEAM Trial Team. United Kingdom back pain exercise and manipulation (UK BEAM) randomised trial: cost effectiveness of physical treatments for back pain in primary care. BMJ 2004;329:1381-5.
Kominski GF, Heslin KC, Morgenstern H, et al. Economic evaluation of four treatments for low-back pain: results from a randomized controlled trial. Med Care 2005;43:428-35.
Indexing Status Subject indexing assigned by NLM MeSH Acute Disease; Adult; Chronic Disease; Cost-Benefit Analysis; Disability Evaluation; Female; Health Care Costs /statistics & Humans; Low Back Pain /classification /economics /therapy; Male; Manipulation, Chiropractic /economics; Patient Satisfaction; Referral and Consultation; numerical data AccessionNumber 22005001575 Date bibliographic record published 30/04/2006 Date abstract record published 30/04/2006 |
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