Univariable meta-regression may be more conservative compared to chi-square in sub-group analyses

Article type
Authors
Foroutan F1, Schandelmaier S1, Sadeghirad B1, Devji T1, Alba C2, Hanna S1, Vandvik PO3, Guyatt G1
1Department of Health Research Methods, Evidence, and Impact, McMaster University
2Heart Failure, Heart Transplant, and Mechanical Circulatory Support, Toronto General Hospital
3Institute of Health and Society, Universitetet i Oslo
Abstract
Univariable meta-regression may be more conservative compared to chi-square in sub-group analyses.

Background: Authors of systematic reviews exploring heterogeneity typically use the chi-square test, the default statistical method for sub-group analysis in most statistical packages. Another analytical method to assess effect modification or heterogeneity of both binary and continuous variables is meta-regression.

Objectives: To explore the extent to which chi-square and meta-regression provide different results for subgroup analysis.

Methods: We present our experience with applying both the chi-square method and a random-effects univariable meta-regression to a recent subgroup analysis in a prognostic review on deterioration of transcatheter aortic valve implants. For this analysis, we used the DerSimonian and Laired random effect model with a Freeman-Tukey transformation. R (version 3.3.2) provided the statistical package for our analyses.

Results: The pooled incidence rate of valve deterioration from 13 observational studies was 28 (95% CI: 2 to 73) per 10 000 patient years. We observed a higher incidence rate in the subgroup of studies with no anti-coagulation at discharge (126, 95% CI: 97 to 160, I2 = 0%) than in the subgroup of studies not reporting on anticoagulation (14, 95% CI: 0.2 to 40, I2 = 87%). The chi-square test showed an interaction p-value of