Return of FEV1 after pulmonary exacerbation in children with cystic fibrosis.

RATIONALE: Lung function (FEV(1)) generally improves during treatment of pulmonary exacerbations in patients with cystic fibrosis (CF). However, it is unclear how often return to previous baseline FEV(1) is achieved.

OBJECTIVES: (1) To determine the proportion of pediatric patients with CF treated for a pulmonary exacerbation who fail to recover to baseline FEV(1) and (2) to identify factors associated with this failure.

METHODS: We performed a case-control analysis of patients from a single pediatric CF center admitted for their first pulmonary exacerbation in 2001-2006. Patients were considered to have recovered to baseline FEV(1) if their best FEV(1) within the 3 months following treatment was >or=95% of the best FEV(1) during the 6 months prior to treatment. Logistic regression was used to estimate associations between clinical characteristics and failure to regain baseline FEV(1).

RESULTS: Of 104 patients, 24 (23.1%) did not recover to baseline FEV(1). The adjusted odds ratio of failure to recover to baseline FEV(1) was 1.49 (95% confidence interval [CI] 1.20, 1.86) for every 5% greater decline in FEV(1) from baseline to admission. In exploratory analyses, the adjusted odds ratios for the failure to recover to baseline were also significantly higher for patients who were evaluated in our CF clinic more frequently between the baseline measurement and admission, were younger, or were insured by Medicaid.

CONCLUSIONS: Approximately one in four patients with CF failed to recover to baseline lung function after a pulmonary exacerbation despite treatment with intravenous antibiotics. Failure to recover to baseline was associated with the degree of decline in FEV(1) that had occurred prior to hospital admission, suggesting opportunities for earlier intervention to improve lung function outcomes. Additional studies are needed to determine how the failure to recover to baseline affects subsequent FEV(1) decline.