Improving the quality of reporting of systematic reviews of dose-response meta-analyses: a cross-sectional survey

BACKGROUND: Dose-response meta-analysis (DRMA) is a useful tool to investigate potential dose-response relationship between certain exposure or intervention and the outcome of interest. A large number of DRMAs have been published in the past several years. However, the standard of reporting for such studies is not known. METHODS: Medline, Embase, and Wiley Library were searched for systematic reviews with DRMAs (SR-DRMAs) published from January 2011 to July 2017. We used the combination of PRISMA and MOOSE statements, containing 33 items, to assess the reporting of included SR-DRMAs. The adherence of reporting was defined as the proportion of SR-DRMAs meeting the reporting requirement of an item. We explored the association between five pre-specified variables with the total score of reporting on both fully as well as each domain of the checklist. RESULTS: In total, 529 SR-DRMAs were eligible. Ten out of 33 items were under reported, and this mainly refers to the methods domain: only a small proportion of SR-DRMAs stated whether a review protocol existed (45, 8.5%); clarified the qualifications of searchers (1.7%); presented full electronic search strategy (25.9%); described any effort to include all available studies (22.9%), described methods for languages other than English (27.4%), and stated the process for selecting studies (20.2%). Multiple regression analysis suggested that studies with more authors (regression coefficient = 0.78; 95% CI: 0.35, 1.20; P < 0.001), published more recently (regression coefficient = 0.38; 95% CI: 0.28 to 0.47; trend P < 0.001), used reporting guideline (regression coefficient = 0.98; 95% CI: 0.68 to 1.32; P < 0.001), and involvement of methodologist (regression coefficient = 0.86; 95% CI: 0.42 to 1.32; P < 0.001) were associated with higher score of reporting. Further regression suggested that the improvement on the quality mainly concentrated on the methods and results domains. CONCLUSIONS: The reporting of SR-DRMAs needs to be further improved, particularly in the issues refer to the methods. The quality of reporting may improve when involving more authors and methodologists and employing any reporting guidelines. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12874-018-0623-6) contains supplementary material, which is available to authorized users.