Quality of systematic reviews with meta-analyses of resveratrol: A methodological systematic review

Recently, several meta-analyses (MAs) have focused on the health effects of resveratrol. However, the methodological and reporting quality of these MAs has not yet been fully evaluated so far. Therefore, the present study evaluated the quality of these MAs through a methodological systematic review. Systematic searches were conducted in PubMed, Embase, Web of Science, and Cochrane Library from inception until May 20, 2022, and PubMed was used to update the search until September 6, 2023. The methodological and reporting quality of the selected MAs was evaluated using AMSTAR-2 and PRISMA 2009. Fifty-one MAs published during 2013-2023 were included. In each review, the number of primary studies ranged from 3 to 37, and the number of participants ranged from 50 to 2114. Among the first-listed primary outcomes, only 23 (45.10%) were "positive." As for the methodological quality, most MAs (44, 86.27%) on resveratrol were rated critically low. Inadequate reporting of the included MAs mainly involved items 2 ("Structured summary"), 5 ("Protocol and registration"), 8 ("Search"), 9 ("Study selection"), 10 ("Data collection process"), 12 ("Risk of bias in individual studies"), and 24 ("Summary of evidence") based on the PRISMA 2009. Additionally, journal's impact factor, number of authors, and funding support were positively associated with the overall methodological quality but were not statistically significant (p > 0.05). Future MAs on resveratrol require better design, implementation, and reporting by following the Cochrane Handbook, AMSTAR-2, and PRISMA.