Here you can find methodological articles published by PERSyst group, with a brief summary of each paper.
Meta-analysis of prevalence: I 2 statistic and how to deal with heterogeneity
How to cite: Migliavaca CB, Stein C, Colpani V, Barker TH, Ziegelmann PK, Munn Z, Falavigna M; Prevalence Estimates Reviews-Systematic Review Methodology Group (PERSyst). Meta-analysis of prevalence: I2 statistic and how to deal with heterogeneity. Res Synth Methods. 2022 May;13(3):363-367.
Summary: Heterogeneity is usually explored with I-squared statistic (I2), but this statistic does not directly inform us about the distribution of effects and frequently systematic reviewers and readers misinterpret this result. In this study, we evaluated a sample of 134 meta-analyses of prevalence. In this sample, the median I2 was 96.9% (IQR 90.5-98.7). From our perspective, in meta-analyses of prevalence the I2 statistics may not be discriminative and should be interpreted with caution, avoiding arbitrary thresholds. To discuss heterogeneity, reviewers should focus on the description of the expected range of estimates, which can be done using prediction intervals and planned sensitivity analysis.
How to cite: Barker TH, Migliavaca CB, Stein C, Colpani V, Falavigna M, Aromataris E, Munn Z. Conducting proportional meta-analysis in different types of systematic reviews: a guide for synthesisers of evidence. BMC Med Res Methodol. 2021 Sep 20;21(1):189.
Summary: Single group data, such as prevalence estimates, present unique challenges for synthesises of evidence. While robust and comprehensive methods exist detailing how researchers can conduct a meta-analysis that compares two (or more) groups against a common intervention, there is a scarcity of methodological guidance available to assist synthesisers of evidence in the conduct, interpretation, and importance of proportional meta-analysis in systematic reviews. This paper presents an overview targeted to synthesisers of evidence and systematic review authors that details the methods, importance, and interpretation of a proportional meta-analysis.
How are systematic reviews of prevalence conducted? A methodological study
How to cite: Borges Migliavaca C, Stein C, Colpani V, Barker TH, Munn Z, Falavigna M; Prevalence Estimates Reviews – Systematic Review Methodology Group (PERSyst). How are systematic reviews of prevalence conducted? A methodological study. BMC Med Res Methodol. 2020 Apr 26;20(1):96.
Summary: The objective of this study was to evaluate the methodology of a sample of systematic reviews of prevalence. We evaluated 235 reviews, published between February 2017 and February 2018. he median number of authors was 5 (interquartile range [IQR] 4–7), the median number of databases searched was 4 (3–6) and the median number of studies included in each review was 24 (IQR 15–41.5). Search strategies were presented for 68% of reviews. Forty five percent of reviews received external funding, and 24% did not provide funding information. Twenty three percent of included reviews had published or registered the systematic review protocol. Reporting guidelines were used in 72% of reviews. The quality of included studies was assessed in 80% of reviews. Nine reviews assessed the overall quality of evidence (4 using GRADE). Meta-analysis was conducted in 65% of reviews; 1% used Bayesian methods. Random effect meta-analysis was used in 94% of reviews; among them, 75% did not report the variance estimator used. Among the reviews with meta-analysis, 70% did not report how data was transformed; 59% percent conducted subgroup analysis, 38% conducted meta-regression and 2% estimated prediction interval; I2 was estimated in 95% of analysis. Publication bias was examined in 48%. The most common software used was STATA (55%). These results point to important inconsistencies regarding how these reviews are conducted, specially in the assessment of methodological quality and the formal synthesis of comparable data.
Quality assessment of prevalence studies: a systematic review
How to cite: Migliavaca CB, Stein C, Colpani V, Munn Z, Falavigna M; Prevalence Estimates Reviews – Systematic Review Methodology Group (PERSyst). Quality assessment of prevalence studies: a systematic review. J Clin Epidemiol. 2020 Nov;127:59-68.
Summary: The objective of the study was to identify items and domains applicable for the quality assessment of prevalence studies. We identified 30 tools: 8 (26.7%) specifically designed to appraise prevalence studies and 22 (73.3%) adaptable for this purpose. We identified 12 unique items in the domain “population and setting”, 16 in the domain “condition measurement”, and 14 in the domain “statistics”. We provided a comprehensive set of items classified by domains that can guide the appraisal of prevalence studies, conduction of primary prevalence studies, and update or development of tools to evaluate prevalence studies.