Increased rate of lung function decline in Australian adolescents with cystic fibrosis.

INTRODUCTION: Though baseline lung function as measured by spirometry in children with cystic fibrosis (CF) has improved, the annual rate of decline has not changed significantly during the critical period of adolescence. The aim of this study was to describe factors associated with longitudinal decline in lung function in a contemporary cohort of children with CF.
METHODS: Best annual lung function data from children attending the CF service of the Royal Children's Hospital Melbourne were reviewed to determine rate of decline in FEV(1) up until time of transfer to an adult center. Mixed models were used to determine the influence of age, sex, genotype, newborn screening, respiratory hospitalization, CF related diabetes mellitus (CFRD), pancreatic insufficiency, Pseudomonas aeruginosa (PsA) infection, and body mass index (BMI) on lung function decline.
RESULTS: Longitudinal lung function data (range 5-20 years) were obtained for 98 patients with CF (55 male). Overall, the annual rate of decline in FEV(1) % predicted for the entire cohort was 1.4% per annum though the greatest rate of FEV1 decline was seen during adolescence (2.6%). Increasing age, homozygous ΔF508 genotype, CFRD, mucoid PsA infection, pancreatic insufficiency and respiratory hospitalizations were all significant predictors of FEV1 decline.
CONCLUSION: FEV(1) declines at its sharpest rate during adolescence even in the presence of newborn screening. Genotype, increasing age, CFRD, PsA infection, pancreatic insufficiency and a greater number of respiratory hospitalizations are all associated with an increased rate of lung function decline in Australian children and adolescents with cystic fibrosis.