Reporting of drug trial funding sources and author financial conflicts of interest in Cochrane and non-Cochrane meta-analyses: a cross-sectional study

OBJECTIVE: To (1) investigate the extent to which recently published meta-analyses report trial funding, author–industry financial ties and author–industry employment from included randomised controlled trials (RCTs), comparing Cochrane and non-Cochrane meta-analyses; (2) examine characteristics of meta-analyses independently associated with reporting funding sources of included RCTs; and (3) compare reporting among recently published Cochrane meta-analyses to Cochrane reviews published in 2010. DESIGN: Review of consecutive sample of recently published meta-analyses. DATA SOURCES: MEDLINE database via PubMed searched on 19 October 2018. ELIGIBILITY CRITERIA FOR SELECTING ARTICLES: We selected the 250 most recent meta-analyses listed in PubMed that included a documented search of at least one database, statistically combined results from ≥2 RCTs and evaluated the effects of a drug or class of drugs. RESULTS: 90 of 107 (84%) Cochrane meta-analyses reported funding sources for some or all included trials compared with 21 of 143 (15%) non-Cochrane meta-analyses, a difference of 69% (95% CI 59% to 77%). Percent reporting was also higher for Cochrane meta-analyses compared with non-Cochrane meta-analyses for trial author–industry financial ties (44% versus 1%; 95% CI for difference 33% to 52%) and employment (17% versus 1%; 95% CI for difference 9% to 24%). In multivariable analysis, compared with Cochrane meta-analyses, the odds ratio (OR) for reporting trial funding was ≤0.11 for all other journal category and impact factor combinations. Compared with Cochrane reviews from 2010, reporting of funding sources of included RCTs among recently published Cochrane meta-analyses improved by 54% (95% CI 42% to 63%), and reporting of trial author–industry financial ties and employment improved by 37% (95% CI 26% to 47%) and 10% (95% CI 2% to 19%). CONCLUSIONS: Reporting of trial funding sources, trial author–industry financial ties and trial author–industry employment in Cochrane meta-analyses has improved since 2010 and is higher than in non-Cochrane meta-analyses.