Pulmonary function outcomes for assessing cystic fibrosis care

Background: Assessing cystic fibrosis (CF) patient quality of care requires the choice of an appropriate outcome measure. We looked systematically and in detail at pulmonary function outcomes that potentially reflect clinical practice patterns. Methods: Epidemiologic Study of Cystic Fibrosis data were used to evaluate six potential outcome variables (2002 best FVC, FEV₁, and FEF_25-75 and rate of decline for each from 2000 to 2002). We ranked CF care sites by outcome measure and then assessed any association with practice patterns and follow-up pulmonary function. Results: Sites ranked in the top quartile had more frequent monitoring, treatment of exacerbations, and use of chronic therapies and oral corticosteroids. The follow-up rate of pulmonary function decline was not predicted by site ranking. Conclusions: Different pulmonary function outcomes associate slightly differently with practice patterns, although annual FEV₁ is at least as good as any other measure. Current site ranking only moderately predicts future ranking.