Pulmonary exacerbations and clinical outcomes in a longitudinal cohort of infants and preschool children with cystic fibrosis

BACKGROUND Pulmonary exacerbations (PEx) in school aged children and adults with cystic fibrosis (CF) lead to increased morbidity and lung function decline. However, the effect of exacerbations in young children with CF is not fully understood. We sought to characterize the frequency and clinical impact of PEx in a pilot study of infants and pre-school aged children with CF. METHODS Thirty young children with CF [median (range) 1.5 years (0.2-4.9)] were prospectively followed for 2 years. Exacerbation frequency (hospitalizations and outpatient antibiotic use) was determined. Chest radiographs were performed at enrollment and study completion and assigned a Brasfield score. Lung function at age 7 years was assessed in a subset of children. The association between PEx frequency, chest radiograph score, and lung function was determined using Spearman correlation coefficients and corresponding 95% confidence intervals. Correlations with an absolute magnitude of 0.3 or greater were considered clinically significant. RESULTS Over 2 years, participants experienced a median of two PEx (range 0-13). Chest radiograph scores at enrollment and study completion were inversely associated with PEx frequency (R = -0.48 and R = -0.44, respectively). The association between frequency of PEx and lung function [forced expiratory volume in 1 s (FEV1)] at age 7 years was small (R = 0.20). Higher forced vital capacity (FVC) at 7 years was associated with more frequent PEx during the study (R = 0.44). CONCLUSIONS Children with worse chest radiograph scores had more frequent PEx over the subsequent 2 years, suggesting a group of patients at higher risk for PEx. Frequent PEx in infants and young children with CF were not associated with lower FEV1 and FVC at 7 years, although spirometry in this age group may not be a sensitive marker of mild lung disease and disease progression.