Low back pain (LBP) is a ‘minor complaint’ in the sense that it does not cost patients’ lives. At the same time, LBP is amongst the leading causes of disability and one of the most common reasons for patients to seek primary care. Chiropractors, osteopaths, physical therapists and general practitioners are among those treating LBP patients, but there is only limited evidence regarding the effectiveness offered by these provider groups.
The aim of this systematic review was to estimate the clinical effectiveness and to systematically review economic evaluations of chiropractic care compared to other commonly used approaches among adult patients with non-specific LBP.
A comprehensive search strategy was conducted to identify 1) pragmatic randomized clinical trials (RCTs) and/or 2) full economic evaluations of chiropractic care for low back pain compared to standard care delivered by other healthcare providers. Studies published between 1990 and 4th June 2015 were considered. The primary outcomes included pain, functional status and global improvement. Study selection, critical quality appraisal and data extraction were conducted by two independent reviewers. Data from RCTs with low risk of bias were included in a meta-analysis to determine estimates of effect sizes. Cost estimates of full economic evaluations were converted to 2015 USD and results summarized.
Six RCTs and three full economic evaluations were included. Five RCTs with low risk of bias compared chiropractic care to exercise therapy (n = 1), physical therapy (n = 3) and medical care (n = 1). The authors found similar effects for chiropractic care and the other types of care. Three low to high quality full economic evaluations studies (one cost-effectiveness, one cost-minimization and one cost-benefit) compared chiropractic to medical care. Highly divergent conclusions (favours chiropractic, favours medical care, equivalent options) were noted for economic evaluations of chiropractic care compared to medical care.
The authors drew the following conclusions: moderate evidence suggests that chiropractic care for LBP appears to be equally effective as physical therapy. Limited evidence suggests the same conclusion when chiropractic care is compared to exercise therapy and medical care although no firm conclusion can be reached at this time. No serious adverse events were reported for any type of care. Our review was also unable to clarify whether chiropractic or medical care is more cost-effective. Given the limited available evidence, the decision to seek or to refer patients for chiropractic care should be based on patient preference and values. Future studies are likely to have an important impact on our estimates as these were based on only a few admissible studies.
This is a thorough and timely review. Its results are transparent and clear, however, its conclusions are, in my view, more than a little odd.
Let me try to re-formulate them such that they are better supported by the actual data: There is no good evidence to suggest that chiropractic care is better or worse that conventional therapeutic approaches currently used for LBP. The pooled sample size dimensions too small to allow any statements about the risks of the various approaches. The data are also too weak for any pronouncements on the relative cost-effectiveness of the various options. Given these limitations, the decision which approach to use should be based on a more comprehensive analysis of the therapeutic risks.
The point I am trying to make is quite simple:
- The fact that RCTs fail to show adverse effects could be due to the small collective sample size and/or to the well-known phenomenon that, in well-controlled trials, adverse effects tend to be significantly rarer than in routine care.
- Hundreds of serious adverse events have been reported after chiropractic spinal manipulations; to these we have to add the fact that ~50% of all chiropractic patients suffer from transient, mild to moderate adverse effects after spinal manipulations.
- If we want to generate a realistic picture of the safety of a therapy, we need to include case-reports, case-series and other non-RCT evidence.
- Conventional treatments of LBP may not be free of adverse effects, but some are relatively safe.
- It seems reasonable, necessary and ethical to consider a realistic picture of the relative risks when deciding which therapy amongst equally (in)effective treatments might be best.
To me, all this seems almost painfully obvious, and I ask myself why the authors of this otherwise sound review failed to consider such thoughts. As one normally is obliged to, the authors included a section about the limitations of their review:
Our review has limitations. First, we did not search the grey literature for clinical effectiveness studies. McAuley et al. showed that the inclusion of results from the grey literature tend to decrease effectiveness estimates in meta-analyses because the unpublished studies tend to report smaller treatment effects. Second, critical appraisal requires scientific judgment that may vary among reviewers. This potential bias was minimized by training reviewers to use a standardized critical appraisal tool and using a consensus process among reviewers to reach decisions regarding scientific admissibility. Most of the original between-group differences and pooled estimates in our meta-analysis did not favour a specific provider group, and we believe it is unlikely that the inclusion of unpublished grey literature would change our conclusions. Third, the low number of clinical trials prevents us from conducting a meaningful investigation for publication bias. Fourth, the majority of the included clinical effectiveness studies (three out of five) and all three economic evaluations were conducted in the United States. Caution should therefore be used when generalizing our findings to other settings or jurisdictions. With respect to economic evaluations in particular, local healthcare systems and insurance plans may have a higher impact on cost than the type of healthcare provider.
Remarkably, this section does not mention their useless assessment of the risks with one word. Why? One answer might be found in the small-print of the paper:
The authors … have the following competing interests: MAB: Personal fees from Ordre des chiropraticiens du Québec for one teaching presentation, outside the submitted work. MJS: Position at the Nordic Institute of Chiropractic and Clinical Biomechanics is funded by the Danish Chiropractic Research Foundation. The Foundation had no role in the study design; in the design and conduct of the study, in the collection, management, analysis, and interpretation of data; in the preparation, review or approval of the manuscript; or in the decision to submit the article for publication. RBDS: Nothing to disclose. JB: Nothing to disclose. PH: Nothing to disclose. AB: Position at the School of Physical and Occupational Therapy at McGill University is funded by the Canadian Chiropractic Research Foundation. The Foundation had no role in the study design; in the design and conduct of the study, in the collection, management, analysis, and interpretation of data; in the preparation, review or approval of the manuscript; or in the decision to submit the article for publication.