How often have I pointed out that most studies of chiropractic (and other alternative therapies) are overtly unethical because they fail to report adverse events? And if you think this is merely my opinion, you are mistaken. This new analysis by a team of chiropractors aimed to describe the extent of adverse events reporting in published RCTs of Spinal Manipulative Therapy (SMT), and to determine whether the quality of reporting has improved since publication of the 2010 Consolidated Standards Of Reporting Trials (CONSORT) statement.
The Physiotherapy Evidence Database and the Cochrane Central Register of Controlled Trials were searched for RCTs involving SMT. Domains of interest included classifications of adverse events, completeness of adverse events reporting, nomenclature used to describe the events, methodological quality of the study, and details of the publishing journal. Data were analysed using descriptive statistics. Frequencies and proportions of trials reporting on each of the specified domains above were calculated. Differences in proportions between pre- and post-CONSORT trials were calculated with 95% confidence intervals using standard methods, and statistical comparisons were analysed using tests for equality of proportions with continuity correction.
Of 7,398 records identified in the electronic searches, 368 articles were eligible for inclusion in this review. Adverse events were reported in 140 (38.0%) articles. There was a significant increase in the reporting of adverse events post-CONSORT (p=.001). There were two major adverse events reported (0.3%). Only 22 articles (15.7%) reported on adverse events in the abstract. There were no differences in reporting of adverse events post-CONSORT for any of the chosen parameters.
The authors concluded that although there has been an increase in reporting adverse events since the introduction of the 2010 CONSORT guidelines, the current level should be seen as inadequate and unacceptable. We recommend that authors adhere to the CONSORT statement when reporting adverse events associated with RCTs that involve SMT.
We conducted a very similar analysis back in 2012. Specifically, we evaluated all 60 RCTs of chiropractic SMT published between 2000 and 2011 and found that 29 of them did not mention adverse effects at all. Sixteen RCTs reported that no adverse effects had occurred (which I find hard to believe since reliable data show that about 50% of patients experience adverse effects after consulting a chiropractor). Complete information on incidence, severity, duration, frequency and method of reporting of adverse effects was included in only one RCT. Conflicts of interests were not mentioned by the majority of authors. Our conclusion was that adverse effects are poorly reported in recent RCTs of chiropractic manipulations.
The new paper suggests that the situation has improved a little, yet it is still wholly unacceptable. To conduct a clinical trial and fail to mention adverse effects is not, as the authors of the new article suggest, against current guidelines; it is a clear and flagrant violation of medical ethics. I blame the authors of such papers, the reviewers and the journal editors for behaving dishonourably and urge them to get their act together.
The effects of such non-reporting are obvious: anyone looking at the evidence (for instance via systematic reviews) will get a false-positive impression of the safety of SMT. Consequently, chiropractors are able to claim that very few adverse effects have been reported in the literature, therefore our hallmark therapy SMT is demonstrably safe. Those who claim otherwise are quite simply alarmist.