Probability of treatment following acute decline in lung function in children with cystic fibrosis is related to baseline pulmonary function

Objective To determine whether the association between high forced expiratory volume in 1 second (FEV₁) and increased rate of decline in FEV₁ in children with cystic fibrosis could be due to less frequent intervention after acute declines (sudden decline events) in FEV₁. Study design Patients with cystic fibrosis aged 6-17 years enrolled in the Epidemiologic Study of Cystic Fibrosis were assessed for a sudden decline event, defined as a 10% relative decline in FEV₁% predicted from an average of 3 consecutive stable baseline spirometries. The likelihood of therapeutic intervention within 14 days before and 56 days after this event was then related to their baseline FEV₁% predicted age-specific decile using a logistic regression adjusting for age group (6-12 years, 13-17 years) and presence of Pseudomonas aeruginosa on respiratory culture. Results A total of 10 888 patients had at least 1 sudden decline event in FEV₁. Patients in the highest FEV₁ decile were significantly less likely than those in the lowest decile to receive intravenous antibiotics (OR, 0.14; 95% CI, 0.11-0.18; P <.001) or be hospitalized (OR, 0.18; 95% CI, 0.14-0.23; P <.001) following decline. Conclusions Children and adolescents with high baseline lung function are less likely to receive a therapeutic intervention following an acute decline in FEV₁, which may explain their greater rate of FEV₁ decline.