Therapeutic effects of oral zinc in acute and persistent diarrhea in children in developing countries: pooled analysis of randomized controlled trials

Background: Zinc deficiency is prevalent in children in developing countrie s. Supplemental zinc provides therapeutic benefits in diarrhea. Objective: We sought to measure the effect of supplemental zinc given with oral rehydration therapy during recovery from acute or persistent diarrhea. Design: We conducted pooled analyses including all available published and unpublished randomized controlled trials of the effects of supplementary or al zinc in children aged < 5 y with acute or persistent diarrhea. We used C ox survival regression analysis to evaluate the overall effect of zinc on c ontinuation of diarrhea and possible differential effects in subgroups divi ded by sex, age, weight-for-height, and initial plasma zinc concentration. Dichotomous outcomes were analyzed by logistic regression. To assess the ef fects of excluding studies without original data from the pooled analyses, effect-size was estimated for all studies by using random-effects models. Results: Zinc-supplemented children had a 15% lower probability of continui ng diarrhea on a given day (95% CI: 5%, 24%) in the acute-diarrhea trials a nd a 24% lower probability of continuing diarrhea (95% CI: 9%, 37%) and a 4 2% lower rate of treatment failure or death (95% CI: 10%, 63%) in the persi stent-diarrhea trials. In none of the subgroup analyses were the 2 subgroup s of each pair significantly different from each other; however, in persist ent diarrhea there tended to be a greater effect in subjects aged < 12 mo, who were male, or who had wasting or lower baseline plasma zinc concentrati ons. Conclusion: Zinc supplementation reduces the duration and severity of acute and persistent diarrhea.