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Most healthcare interventions tested in Cochrane Reviews are not effective according to high quality evidence: a systematic review and meta-analysis

journal contribution
posted on 16.06.2022, 10:25 authored by Jeremy Howick, Despina Koletsi, John PA Ioannidis, Claire MadiganClaire Madigan, Nikolaos Pandis, Martin Loef, Harald Walach, Sebastian Sauer, Jos Kleijnen, Jadbinder Seehra, Tess Johnson, Stefan Schmidt

Objective

To estimate the proportion of healthcare interventions tested within Cochrane Reviews that are effective according to high-quality evidence.

Study design and setting

We selected a random sample of 2428 (35%) of all Cochrane Reviews published between 1 January 2008 and 5 March 2021. We extracted data about interventions within these reviews that were compared with placebo, or no treatment, and whose outcome quality was rated using Grading of Recommendations Assessment, Development and Evaluation (GRADE). We calculated the proportion of interventions whose effectiveness was based on high-quality evidence according to GRADE, had statistically significant positive effects, and were judged as beneficial by the review authors. We also calculated the proportion of interventions that suggested harm.

Results

Of 1567 eligible interventions, 87 (5.6%) had high quality evidence on first-listed primary outcomes, positive, statistically significant results and were rated by review authors as beneficial. Harms were measured for 577 (36.8%) interventions, 127 of which (8.1%) had statistically significant evidence of harm. Our dependence on the reliability of Cochrane author assessments (including their GRADE assessments) was a potential limitation of our study.

Conclusion

Most healthcare interventions studied within recent Cochrane Reviews are not supported by high quality evidence, and harms are under-reported.

History

School

  • Sport, Exercise and Health Sciences

Published in

Journal of Clinical Epidemiology

Volume

148

Pages

160 - 169

Publisher

Elsevier

Version

AM (Accepted Manuscript)

Rights holder

© Elsevier

Publisher statement

This paper was accepted for publication in the journal Journal of Clinical Epidemiology and the definitive published version is available at https://doi.org/10.1016/j.jclinepi.2022.04.017

Acceptance date

12/04/2022

Publication date

2022-04-18

Copyright date

2022

ISSN

0895-4356

Language

en

Depositor

Dr Claire Madigan. Deposit date: 19 May 2022