Background: The term “meta-epidemiology” is relatively recent; it first appeared in literature in 1997, and in 2002, a methodological guidance was published for “meta-epidemiological” studies that evaluate effect of trial characteristics on effect sizes. However, it has been reported that methodology of “meta-epidemiological” studies is not standardized and that terminology used for such studies varies. Therefore, it appears that there is an ambiguity in the understanding and use of the term meta-epidemiological study in the research community.
Objectives: To analyze descriptors and definitions of meta-epidemiological studies in published literature, as well as study design of articles that were self-described as meta-epidemiological studies.
Methods: This was a primary methodological (research-on-research) study in which units of analysis were published manuscripts. We searched MEDLINE and Embase on August 6, 2019. We extracted definitions of meta-epidemiological studies. From studies self-identified as meta-epidemiological, we extracted their aim, description of the study designs, statistical methods used, unit of analysis, whether they had made their study protocol publicly available (and where), and whether they mentioned that they used any reporting guideline/checklist to report their study.
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. There were 127 (73%) full-text journal articles that authors self-identified with an expression indicating that this was “meta-epidemiological” study or that “meta-epidemiological” analysis was performed, although with varied terminology. Definitions and descriptions of meta-epidemiological studies were found in 40 (25%) records. Some of them defined them broadly as research that examines influence of trial/study characteristics on effect estimates, while for some it appeared that the definition described completely different designs (eg. surveys). Less than a half of those 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: Authors of published literature use heterogeneous definitions and descriptors for meta-epidemiological studies. Methodological research-on-research studies are also labeled as meta-epidemiological. Research community would benefit from consensus about definition of a meta-epidemiological study.
Patient or healthcare consumer involvement: This was a research methodology study and it did not include patient or healthcare consumers.