What is a meta-epidemiological study? Analysis of published literature indicated heterogeneous study designs and definitions

Aim: To analyze descriptors/definitions of meta-epidemiological studies as well as study design of articles that were self-described as meta-epidemiological studies. Methods: We searched MEDLINE and Embase on 6 August 2019. We extracted definitions of meta-epidemiological studies, as well as study designs, statistics and units of analysis that were reported in studies self-labelled as meta-epidemiological studies. Results: We included 175 information sources in the analysis. Definitions of meta-epidemiological studies varied and some studies used the term meta-epidemiological study to describe methodological research-on-research studies. Less than a half of the studies (n = 54; 42.9%) used the two-step meta-epidemiological approach in data analysis. Among studies self-labelled as meta-epidemiological, 9.4% reported registration in PROSPERO and 11% indicated they reported the study in line with PRISMA. Conclusion: Research community would benefit from consensus about definition of meta-epidemiological study.