Side effects are incompletely reported in peer-reviewed journal articles describing research findings on the clinical benefits of drugs and other medical treatments, according to a systematic review carried out by Su Golder of University of York, UK, and colleagues published in PLOS Medicine.

The clinical benefits of new drugs are usually tested in randomized clinical trials, in which patients are randomly assigned to receive a drug or placebo, before drugs can be prescribed widely. Adverse events, or side effects, are also routinely collected in such trials, and should be reported in journal articles to give a clear picture of the benefit and risks of new treatments. Golder and colleagues systematically gathered studies which compared published reports of clinical studies with unpublished information on the same studies gathered from conference reports, pharmaceutical companies' clinical study reports and other sources.

Golder and colleagues found that a median of 64% of side effects would have been missed by readers looking only at published reports about the medical treatments studied. The authors conclude that full reporting of adverse events in journal articles is essential to allow patients and doctors to assess the balance between the benefits and harms of medical treatments, noting "the urgent need to progress towards full disclosure and unrestricted access to information from clinical trials".

This report is independent research arising from a Postdoctoral Research Fellowship, SG PDF-2014-07-041, supported by the National Institute for Health Research. No funding bodies had any role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

The authors have declared that no competing interests exist.

Article: Reporting of Adverse Events in Published and Unpublished Studies of Health Care Interventions: A Systematic Review, Golder S, Loke YK, Wright K, Norman G, PLOS Medicine, doi:10.1371/journal.pmed.1002127, published 20 September 2016.