In my previous articles about chiropractic, including a recent review of veterinary spinal manipulation for Science-Based Medicine, I have acknowledged that despite the nonsense of the theory behind chiropractic (the non-existent “vertebral subluxation”), there is at least some evidence in humans that it can be as useful for lower back pain as conventional therapies. However, some reviews have questioned whether the effect seen is clinically meaningful. Now, in an apparent example of the Decline Effect in action, the latest Cochrane review update has further downgraded the effects of chiropractic from statistically but not clinically significant to non-existent.
Rubinstein SM, Terwee CB, Assendelft WJ, de Boer MR, van Tulder MW. Spinal manipulative therapy for acute low back pain: an update of the Cochrane review. Spine (Phila Pa 1976). 2013 Feb 1;38(3):E158-77.
This review added 26 research studies involving over 2600 patients to the studies previously reviewed. Of these, 6 studies (30%) were at low risk of bias based on the quality of their execution. Spinal manipulative therapy (SMT, i.e. chiropractic) was compared with fake chiropractic, other inert placebo therapies, and other therapies thought to be beneficial for acute lower back pain as both the primary and an added (adjunct) therapy. The review concluded:
SMT is no more effective for acute low back pain than inert interventions, sham SMT or as adjunct therapy. SMT also seems to be no better than other recommended therapies.
In other words, when all the studies done are taken together, there is no evidence chiropractic has a benefit for acute lower back pain. Any other therapy, including placebos known to have no effects at all, is just as good.
The authors, as always, acknowledged that many of the studies were of poor quality, and they suggested that further high-quality research could affect this conclusion. But despite decades of intensive study, and widespread use, chiropractic is still unable to demonstrate its value for even the most plausible and seemingly appropriate use, treating back pain. The more evidence we collect, the less reason there is to believe this therapy is worth trying.