Lung function from infancy to the preschool years after clinical diagnosis of cystic fibrosis

Rationale: After recent standardization of forced expiratory maneuvers for both infants and preschool children, longitudinal measurements are now possible from birth. Objectives: The aim of this study was to investigate the evolution of lung function during the first 6 years of life after a clinical diagnosis of cystic fibrosis (CF) in infancy in children with CIF and in healthy control subjects. Methods: The raised volume technique was used during infancy and incentive spirometry during the preschool years. Measurements and Main Results: Forty-eight children with CIF and 33 healthy control subjects had up to seven (median, 3) measurements. Over these early years, the diagnosis of CIF itself accounted for a significant mean reduction of 7.5% (95% confidence interval, 0.9-13.6%) in FEV0.75 and 15.1% (95% confidence interval, 3.6-25.3%) in FEF25-75. Wheeze on auscultation, recent cough, and Pseudomonas aeruginosa (PsA) infection (even if apparently effectively treated) were all independently associated with further reductions in lung function. Premorbid lung function did not predict infection with PsA. Conclusions: This is the first study to describe physiologic measurements from infancy through the preschool years in subjects with CIF and healthy control subjects, the understanding of which is critical for future intervention trials. Airflow obstruction in uncomplicated CIF persists through the preschool years despite treatment, with PsA acquisition being associated with further deterioration in lung function, even when apparently eradicated. This suggests that new therapies are needed to treat the airflow obstruction of uncomplicated CF, and rigorous strategies to prevent PsA acquisition.