[Bronchiolitis among infants under 1 year of age in France: epidemiology and factors associated with mortality].

Little information is available on the characteristics of infants hospitalized for acute bronchiolitis in France. An analysis of hospital records (PMSI) was conducted at the national level to describe the cases of bronchiolitis that require hospitalization among infants under 1 year of age and the factors associated with death. The analysis of all admissions that occurred during 2009, for which the diagnosis of acute bronchiolitis was recorded in the PMSI database for infants aged less than 1 year, was performed. Cases were described according to age, sex, underlying conditions (including bronchopulmonary dysplasia, cystic fibrosis, and congenital heart disease), length of hospital stay, recurrent admissions, admission to an intensive care unit (ICU), and use of assisted ventilation. Factors associated with death during hospitalization were studied by logistic regression. The hospitalization rate was 35.8 per 1000 infants under 1 year in 2009 in France. Approximately 10% of hospitalized infants required ICU admission. Twenty-two infants died. The estimated case-fatality rate was 0.08% among hospitalized infants and 0.56% for those hospitalized in the ICU. Mortality among all infants under 1 year was 2.6/10(5) in France. Factors associated with death were bronchopulmonary dysplasia (OR=6.7, 95% CI [1.5-29.8]), hospitalization in an ICU (OR=6.46, 95% CI [2.4-17.4]), and the use of assisted ventilation (OR=6.2, 95% CI [2.2-17.1]). This study has enabled the quantification of the rate of hospitalization and mortality, and a better description of infants who need hospitalization. The results are consistent with international literature, but further prospective analysis will be needed to better describe the cases at higher risk, aiming to improve their management.