Enteroaggregative Escherichia coli and acute diarrhea in children: a meta-analysis of South Asian populations

The purpose of this investigation was to evaluate the association of enteroaggregative Escherichia coli (EAEC) with acute diarrhea in children of South Asian populations. Our meta-analysis included 18 studies published between 1989 and 2011. The odds ratio (OR) was used to evaluate all available observational epidemiology studies. Modifying effects on the overall OR were approached with outlier, subgroup, cumulative, and cumulative recursive analyses. Synthesis of the 18 observational studies revealed an association between EAEC carriage and acute diarrhea, with an overall OR of 1.51, which was significant (p = 0.008), heterogeneous (P-heterogeneity < 0.0001), and unaffected by outlier analysis. This analysis, however, affected the subgroups by eliminating the following: (i) heterogeneity (from P-heterogeneity < 0.0001 to 0.30-0.72) of pooled ORs in the underpowered (OR 1.37, p = 0.15), Indian (OR 1.92, p = 0.09), and hospital-based (OR 1.66, p = 0.06) studies; (ii) non-significance of these three subgroups (OR 1.56-2.01, p < 0.0001-0.003); (iii) significance of the high-powered studies (from OR 1.70, p = 0.02 to OR 1.15, p = 0.28); (iv) heterogeneity (from P-heterogeneity < 0.0001-0.0002 to 0.11-0.15) of pooled ORs in period three (OR 1.85, p = 0.14), population-based (OR 1.36, p = 0.09), and pCVD432 (OR 1.53, p = 0.07) studies. In general, outlier treatment increased precision with the narrowing of confidence intervals, overall, and in the subgroups. Cumulative meta-analysis generally resulted in increases in the frequencies of significant effects and of heterogeneity. This meta-analysis on observational studies suggests that the association between EAEC and acute diarrhea in children is that of increased risk. This effect generally comes from heterogeneous studies of South Asian populations, but is modified with outlier and subgroup treatments.