METHODS: We conducted a population-based retrospective cohort study of 252,738 healthy infants enrolled in the Tennessee Medicaid Program from 1995 – 2008. During infants’ first six months of age, winter virus season diagnoses of bronchiolitis (ICD codes 466.1 and 480.1) were considered to be exposed cases. During the second six months of age, outcomes of otitis media, pneumonia, and/or ever using antibiotics were captured. We also stratified our analysis by maternal history of asthma.
RESULTS: We identified 52,048 infants with bronchiolitis in the first six months of life. Infants with bronchiolitis had increased rates of ever having otitis media (605.8/1,000 vs. 444.5/1,000, 36% increase), pneumonia (79.4/1,000 vs. 25.9/1,000, 207% increase), and antibiotic utilization (766.8/1,000 vs. 596.5/1,000, 29% increase) compared to infants without bronchiolitis. Among eligible infants, bronchiolitis exposure increased relative risk for otitis media (Adjusted odds ratio [AOR]: 1.88, 95% confidence interval [95%CI]: 1.84, 1.92), pneumonia (AOR: 3.19, 95%CI: 3.06, 3.33), and antibiotic utilization (AOR: 2.16, 95%CI: 2.12, 2.21). There was no interaction between bronchiolitis and maternal history of asthma on all outcomes (p>0.25).
CONCLUSIONS: Infant bronchiolitis during RSV season is associated with an increased risk of subsequent otitis media, pneumonia, and antibiotic utilization, independent of maternal asthma.