How often do we hear that chiropractic is safe because numerous trials reported no adverse events? This systematic review tested whether there has been a change in the reporting of adverse events associated with spinal manipulation in randomized clinical trials (RCTs) since 2016.
Databases were searched from March 2016 to May 2022: MEDLINE (Ovid), Embase, CINAHL, ICL, PEDro, and Cochrane Library. Domains of interest (pertaining to adverse events) included: completeness and location of reporting; nomenclature and description; spinal location and practitioner delivering manipulation; methodological quality of the studies and details of the publishing journal. Frequencies and proportions of studies reporting on each of these domains were calculated. Univariable and multivariable logistic regression models were fitted to examine the effect of potential predictors on the likelihood of studies reporting on adverse events.
5399 records were identified by the electronic searches, of which 154 (2.9%) were included in the analysis. Of these, 94 (61.0%) reported adverse events with only 23.4% providing an explicit description of what constituted an adverse event. Reporting of adverse events in the abstract has increased (n=29, 30.9%) while reporting in the results section has decreased (n=83, 88.3%) over the past 6 years. Spinal manipulation was delivered to 7518 participants in the included studies. No serious adverse events were reported in any of these studies.
The authors concluded as follows: while the current level of reporting of adverse events associated with spinal manipulation in RCTs has increased since our 2016 publication on the same topic, the level remains low and inconsistent with established standards. As such, it is imperative for authors, journal editors and administrators of clinical trial registries to ensure there is more balanced reporting of both benefits and harms in RCTs involving spinal manipulation.
This article is clearly relevant to our discussions about adverse events after spinal manipulation. However, I find it far too uncritical. This might be due to the affiliations of some of the authors:
- Integrative Spinal Research Group, Department of Chiropractic Medicine, University Hospital Balgrist and University of Zurich, Zurich, Switzerland.
- Department of Chiropractic, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia.
Interestingly, the authors stated that they have no conflict of interest. Also interesting is the fact that they do not cite our paper from 2012. I, therefore, take the liberty of doing it:
Objective: To systematically review the reporting of adverse effects in clinical trials of chiropractic manipulation.
Data sources: Six databases were searched from 2000 to July 2011. Randomised clinical trials (RCTs) were considered, if they tested chiropractic manipulations against any control intervention in human patients suffering from any type of clinical condition. The selection of studies, data extraction, and validation were performed independently by two reviewers.
Results: Sixty RCTs had been published. Twenty-nine RCTs did not mention adverse effects at all. Sixteen RCTs reported that no adverse effects had occurred. 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.
Conclusions: Adverse effects are poorly reported in recent RCTs of chiropractic manipulations.
In percentage terms the results are similar. What is very different is that the authors of the new paper merely lament that the level remains low and inconsistent with established standards, while we make it clear in the abstract that adverse effect reporting is poor and in the paper identify this deficit as a violation against research ethics and thus as a form of scientific misconduct.
In view of all this, let me re-phrase the last sentence of the authors’ conclusion:
it is imperative for authors, journal editors, and administrators of clinical trial registries to ensure that researchers adhere to accepted ethical standards and that scientific misconduct no longer gets published.