Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department

Robledo-Aceves, Mireya; Moreno-Peregrina, María de Jesús; Velarde-Rivera, Fernando; Ascencio-Esparza, Elba; Preciado-Figueroa, Francisco M.; Caniza, Miguela A.; Escobedo-Melendez, Griselda

The continuous variable data are reported as the mean and standard deviation (SD). The demographic data, respiratory viruses detected, and risk factors are given as simple frequencies and proportions. Statistical associations were determined by Student t test, Chi-square test, or Fisher exact test, when appropriate. Bivariate analysis was performed using Chi-square test and odds ratio (OR) calculated for risk factors. A Pvalue < .05 was considered statistically significant, and the confidence interval (CI) was set at 95%. All risk factors with significant OR (P < .05) and those with P < .20 were chosen for further evaluation. Logistic regression was used to analyze independent risk factors. Two models were built using enter and conditional forward-selection methods, and then a final model was built. The risk factors that significantly changed the Chisquare value of the model were preserved. The following risk factors or protective variables were entered: exposure to cigarette smoking, having completed the vaccination schedule for the patient's age, breastfeeding for at least 6 months (in children older 6 months of age), a family history of asthma, and male sex.