Twenty-five studies were included in the meta-regression for CD and ODD (see Table 1). The pooled prevalence of CD was estimated as 3.2% (SE .53), which was associated with significant heterogeneity of estimates (p < 0.001). In the multivariate meta-regression model, requirement of impairment for diagnosis (coef=−4.42; SE=1.45; p=.006) and diagnostic criteria (coef=−2.36; SE=1.13; p=.049) were the only covariates that remained significantly associated with heterogeneity of results for CD following the successive deletion of non-significant variables. The continent where the study was conducted was not associated with the heterogeneity of CD estimates (p=.389). The pooled prevalence of ODD was estimated as 3.3% (SE .45), which was associated with significant heterogeneity of estimates (p < 0.001). In the multivariate meta-regression model, age (coef=−3.42; SE=1.16; p=.013) was the only covariate that remained significantly associated with heterogeneity of results for ODD following the successive deletion of non-significant variables. The continent where the study was conducted was not associated with the heterogeneity of estimates (p=.657) of this disorder.
