Year-to-year changes in lung function in individuals with cystic fibrosis

Background: We examined the year-to-year change in FEV(1) for individuals and the overall cystic fibrosis population to better understand how individual trends may differ from population trends. Methods: We calculated individual yearly changes using the largest annual FEV(1), percent predicted (FEV(1)%) measurement in 20,644 patients (6-45 years old) included in the Epidemiologic Study of Cystic Fibrosis. We calculated yearly population changes using age-specific medians. Results: FEV(1)% predicted decreased 1-3 points per year for individuals, with maximal decreases in 14-15 year olds. Population changes agreed with individual changes up to age 15; however after age 30, yearly population change approximated zero while individual FEV(1)% predicted decreases were 1-2 points per year. Conclusions: Adolescents have the greatest FEV(1)% predicted decreases; however, loss of FEV(1) is a persistent risk in 6-45 year old CF patients. Recognizing individual year-to-year changes may improve patient-specific care and may suggest new methods for measuring program quality. (C) 2010 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.