Identifying risk factors for vomiting during diarrhea: A secondary analysis of a randomized trial of zinc supplementation

Objectives: Supplemental zinc during acute diarrhea reduces illness duration but also increases vomiting. In a recent trial, we found that children receiving lower daily doses of zinc (5 mg or 10 mg vs. 20 mg) had lower rates of vomiting with comparable stool output and duration of diarrhea. We performed a secondary analysis to identify sociodemographic and clinical factors associated with vomiting in children with acute diarrhea. Methods: We performed a secondary data analysis of 4500 children aged 6–59 months with an acute episode of diarrhea (<72 h before enrollment) in a randomized, double-blind controlled trial in India and Tanzania. To identify clinically important risk factors for overall, regimen-related, and regimen-unrelated vomiting, we created log-binomial models with relative risks (RRs) and 95% confidence intervals (CIs). Results: The trial enrolled 4500 children, of whom 1203 (26.7%) had any vomiting. After adjusting for multiple demographic and clinical characteristics, the presence of dehydration (RR: 1.45, 95% CI: 1.10–1.92), being underweight (RR: 1.22, 95% CI: 1.05–1.41), receipt of the rotavirus vaccine (RR: 1.89, 95% CI: 1.69–2.12), and household wealth above the median (RR: 1.17, 95% CI: 1.07–1.29) were factors associated with an increased risk of vomiting. Rotavirus vaccine receipt was nearly 100% concordant with the study site of Tanzania. Older age and lower zinc dosing were associated with a lower risk of vomiting. Conclusions: Young, underweight, or dehydrated children are more likely to have concurrent vomiting with zinc supplementation. Identification of these factors may allow providers to better monitor such children, thus reducing the chances of recurrent dehydration or inadequate dietary intake.