Examining the quality of evidence to support the effectiveness of interventions: an analysis of systematic reviews

ObjectiveThis analysis examines the quality of evidence (QOE) for 1472 outcomes linked to interventions where the QOE was rated in 42 systematic reviews of randomised clinical trials and/or observational studies across different topics.SettingNot applicable.Participants76 systematic reviews.Primary and secondary outcome measuresStrength of evidence ratings by initial reviewers.ResultsAmong 76 systematic reviews, QOE ratings were available for only 42, netting 1472 comparisons. Of these, 57% included observational studies; 4% were rated as high and 12% as moderate; the rest were low or insufficient. The ratings varied by topic: 74% of the surgical study pairs were rated as low or insufficient, compared with 82% of pharmaceuticals and 86% of device studies, 88% of organisational, 91% of lifestyle studies, and 94% of psychosocial interventions.ConclusionsWe are some distance from being able to claim evidence-based practice. The press for individual-level data will make this challenge even harder.