Risk factors for bronchiolitis hospitalization in infants: A French nationwide retrospective cohort study over four consecutive seasons (2009-2013).

ABSTRACT

OBJECTIVES: Large studies are needed to update risk factors of bronchiolitis hospitalization. We performed a nationwide analysis of hospitalization rates for bronchiolitis over four consecutive bronchiolitis seasons to identify underlying medical disorders at risk of bronchiolitis hospitalization and assess their frequency. METHODS: Data were retrieved from the French National Hospital Discharge database. Of all infants discharged alive from maternity wards from January 2008 to December 2013 in France (N = 3,884,791), we identified four consecutive cohorts at risk of bronchiolitis during the seasons of 2009-2010 to 2012-2013. The main outcome was bronchiolitis hospitalization during a season. Individual risk factors were collected. RESULTS: Among infants, 6.0% were preterm and 2.0% had ≥1 chronic condition including 0.2% bronchopulmonary dysplasia (BPD) and 0.2% hemodynamically significant congenital heart disease (HS-CHD). Bronchiolitis hospitalization rates varied between seasons (min 1.26% in 2010-2011; max 1.48% in 2012-2013; p<0.001). Except omphalocele, the following conditions were associated with an increased risk for bronchiolitis hospitalization solid organ (9.052; 95% CI, 4.664-17.567) and stem cell transplants (6.012; 95% CI, 3.441-10.503), muscular dystrophy (4.002; 95% CI, 3.1095-5.152), cardiomyopathy (3.407; 95% CI, 2.613-4.442), HS-CHD (3.404; 95% CI, 3.153-3.675), congenital lung disease and/or bronchial abnormalities, Down syndrome, congenital tracheoesophageal fistula, diaphragmatic hernia, pulmonary hypertension, chromosomal abnormalities other than Down syndrome, hemodynamically non-significant CHD, congenital abnormalities of nervous system, cystic fibrosis, cleft palate, cardiovascular disease occurring during perinatal period, and BPD. CONCLUSION: Besides prematurity, BPD, and HS-CHD, eighteen underlying conditions were associated with a significant increased risk for bronchiolitis hospitalization in a nationwide population.