Many of you will know that JAMA is one of the most respected medical journals. It is therefore surprising that, within the period of a few days, they published not one but two dodgy RCTs of alternative treatments.
The new trial was aimed at determining whether the addition of chiropractic care to usual medical care results in better pain relief and pain-related function when compared with usual medical care alone.
The study was designed as a pragmatic comparative effectiveness clinical trial using adaptive allocation was conducted from September 28, 2012, to February 13, 2016, at three US military medical centres. Eligible participants were active-duty US service members aged 18 to 50 years with low back pain from a musculoskeletal source. The intervention period was 6 weeks. Usual medical care included self-care, medications, physical therapy, and pain clinic referral. Chiropractic care included spinal manipulative therapy in the low back and adjacent regions and additional therapeutic procedures such as rehabilitative exercise, cryotherapy, superficial heat, and other manual therapies.
Primary outcomes were low back pain intensity (Numerical Rating Scale; scores ranging from 0 [no low back pain] to 10 [worst possible low back pain]) and disability (Roland Morris Disability Questionnaire; scores ranging from 0-24, with higher scores indicating greater disability) at 6 weeks. Secondary outcomes included perceived improvement, satisfaction (Numerical Rating Scale; scores ranging from 0 [not at all satisfied] to 10 [extremely satisfied]), and medication use.
In total, 750 patients were enrolled. Statistically significant site × time × group interactions were found in all models. Adjusted mean differences in scores at week 6 were statistically significant in favour of usual medical care plus chiropractic care compared with usual medical care alone overall for low back pain intensity (mean difference, −1.1; 95% CI, −1.4 to −0.7), disability (mean difference, −2.2; 95% CI, −3.1 to −1.2), and satisfaction (mean difference, 2.5; 95% CI, 2.1 to 2.8) as well as at each site. Adjusted odd ratios at week 6 were also statistically significant in favour of usual medical care plus chiropractic care overall for perceived improvement (odds ratio = 0.18; 95% CI, 0.13-0.25) and self-reported pain medication use (odds ratio = 0.73; 95% CI, 0.54-0.97). No serious adverse events were reported.
The authors concluded that chiropractic care, when added to usual medical care, resulted in moderate short-term improvements in low back pain intensity and disability in active-duty military personnel. This trial provides additional support for the inclusion of chiropractic care as a component of multidisciplinary health care for low back pain, as currently recommended in existing guidelines. However, study limitations illustrate that further research is needed to understand longer-term outcomes as well as how patient heterogeneity and intervention variations affect patient responses to chiropractic care.
Regular readers will have spotted it straight away: This trial follows the infamous ‘A+B versus B’ design. It will almost always generate a positive result – so much so that it is a waste of time to run the study because we know its findings before it has started. And if this is so, the trial is arguably even unethical.
The reason is, of course, that the study design does not control for placebo effects. And this means that even an utterly useless treatment will produce a (false-positive) result as long as it generates a placebo effect. Some of the authors of the present study are experienced researchers and clearly know all this. This is why they call their study a ‘pragmatic’ trial. But even with pragmatic trials, one cannot get away with murder!
As far as I can see, there are even two ‘murders’ here:
- The authors stated that their aim was to determine whether the addition of chiropractic care to usual medical care results in better pain relief and pain-related function when compared with usual medical care alone. I would argue that their study did not live up to this aim. As it did not control for placebo effects, it cannot possibly test the effectiveness of chiropractic care per se.
- The authors concluded that their trial provides additional support for the inclusion of chiropractic care as a component of multidisciplinary health care for low back pain. I would argue that this is quite simply wrong. The results are in perfect agreement with the assumption that chiropractic care is a placebo, and few would argue that the inclusion of a pure placebo can be recommended.
Compared to these major issues, my other concerns are mere trivialities:
- The trial tested spinal manipulation plus a whole bunch of physiotherapeutic intervention. I bet my last shirt that the chiro-community will claim that it demonstrated the effectiveness of chiropractic spinal manipulations. Already the very first sentence of the present paper’s discussion section goes into this direction: The changes in patient-reported pain intensity and disability as well as satisfaction with care and low risk of harms favoring UMC with chiropractic care found in this pragmatic clinical trial are consistent with the existing literature on spinal manipulative therapy…
- In their abstract, the authors (several of whom are chiropractors) state that there were no serious adverse effects (the paper is extremely thin on providing details about how adverse effects were assessed, verified, categorised etc.). What about non-serious adverse effects (arguably LBP is a minor condition, so minor adverse effects are relevant!)? In the paper, they enlighten us that of the 43 adverse effects reported by participants receiving UMC with chiropractic care, 38 were described as muscle or joint stiffness attributed to chiropractic care (37 events) or physical therapy (1 event), 1 was reported as indistinct symptoms following an epidural injection, 3 were described as pain, tingling, or sensitivity in an extremity without reference to a specific treatment, and 1 was a lower-extremity burning sensation for 20 minutes following spinal manipulative therapy. In my view, this is sufficiently important to be mentioned also in the abstract.
- The authors remain totally silent when it comes to the discussion of the effect sizes. To me, they seem to be moderate. Are they at all clinically relevant. I feel that the discussion of a PRAGMATIC trial must include this pragmatically important issue.