Thirty years ago, and a quarter of a century after randomized trials had become widely accepted, Archie Cochrane reproached the medical profession for not having critical summaries of all randomized controlled trials. At that time, there were about 14 reports of trials published per day.
There are now 75 clinical trials and 11 systematic reviews of trials published every day, with no signs of slowing. How will researchers cope with the volume and the continued poor quality of many of these studies, ask a group in PLoS Medicine.
Systematic reviews obviously have had terrific success - the authors cite reviews finding postoperative radiotherapy after surgical treatment of breast cancer was associated with a previously unrecognized increased risk of death and how reviews challenged beliefs about vitamin C and the common cold.
But as reviews spiked, quality suffered, and analyzing the history and growth of reviews of evidence, the authors recommend that we must now reduce unnecessary trials and prioritize truly systematic review of the literature, so that the needs of patients, clinicians, and policymakers are met.
"Streamlining and innovation in methods of systematic reviewing are necessary to enable valid answers to be found for most patient questions," argue the authors, and "clinicians and patients require open access to these important resources."
Citation: Bastian H, Glasziou P, Chalmers I (2010) Seventy-Five Trials and Eleven Systematic Reviews a Day: How Will We Ever Keep Up? PLoS Med 7(9): e1000326. doi:10.1371/journal.pmed.1000326