Metaprop: a Stata command to perform meta-analysis of binomial data

Abstract

BackgroundMeta-analyses have become an essential tool in synthesizing evidence on clinical and epidemiological questions derived from a multitude of similar studies assessing the particular issue. Appropriate and accessible statistical software is needed to produce the summary statistic of interest.MethodsMetaprop is a statistical program implemented to perform meta-analyses of proportions in Stata. It builds further on the existing Stata procedure metan which is typically used to pool effects (risk ratios, odds ratios, differences of risks or means) but which is also used to pool proportions. Metaprop implements procedures which are specific to binomial data and allows computation of exact binomial and score test-based confidence intervals. It provides appropriate methods for dealing with proportions close to or at the margins where the normal approximation procedures often break down, by use of the binomial distribution to model the within-study variability or by allowing Freeman-Tukey double arcsine transformation to stabilize the variances. Metaprop was applied on two published meta-analyses: 1) prevalence of HPV-infection in women with a Pap smear showing ASC-US; 2) cure rate after treatment for cervical precancer using cold coagulation.ResultsThe first meta-analysis showed a pooled HPV-prevalence of 43% (95% CI: 38%-48%). In the second meta-analysis, the pooled percentage of cured women was 94% (95% CI: 86%-97%).ConclusionBy using metaprop, no studies with 0% or 100% proportions were excluded from the meta-analysis. Furthermore, study specific and pooled confidence intervals always were within admissible values, contrary to the original publication, where metan was used.Electronic supplementary materialThe online version of this article (doi:10.1186/2049-3258-72-39) contains supplementary material, which is available to authorized users.

Viral infection in community-acquired pneumonia: a systematic review and meta-analysis

“…The meta-analyses were carried out with the statistical software package Stata 10 (StataCorp LP, College Station, TX, USA). We used the commands "metaprop" for meta-analysis of proportion, and "metan" for meta-analysis of mortality [15,16].…”

Closure, Anticoagulation, or Antiplatelet Therapy for Cryptogenic Stroke With Patent Foramen Ovale: Systematic Review of Randomized Trials, Sequential Meta‐Analysis, and New Insights From the CLOSE Study

“…The 95% CI of the incidence was calculated using the Wilson method 27. Estimates of the incidence of recurrent stroke were pooled after Freeman–Tukey double arcsine method and then back transformed onto the original scale 28. The number needed to treat (with its 95% CI) to prevent 1 recurrent stroke during 1 person‐year exposure was calculated based upon the pooled incidence of recurrent stroke in the antithrombotic group and the pooled risk ratio for stroke recurrence (PFO closure versus antithrombotic therapy) 29…”

A mixed-method systematic review and meta-analysis of mental health professionals' attitudes toward smoking and smoking cessation among people with mental illnesses

“…Pooling of proportions within each category and within the higher‐level groups was carried out in Stata version 13 using standard methodology 31. Proportions were first transformed using the Freeman–Tukey double arcsine method, pooled with a random effects meta‐analysis with the ‘metan’ command to account for heterogeneity, and then back‐transformed to proportions.…”