High medical costs of treatment of severe bronchiolitis in infants impose a severe economic burden, especially in tropical middle-income countries. There is a critical need therefore to explore the risk factors concerned. In our retrospective cohort study, we included all infants younger than two years admitted in Rionegro, Colombia, owing to bronchiolitis. We used log-binomial regression and estimate prevalence ratios. Out of a total of 417 included, 300 (72.12%) had severe bronchiolitis, with respiratory syncytial virus and current exposure to cigarette smoking being independent predictors.

Keywords: Bronchiolitis; respiratory syncytial virus; smoking.