Factors influencing outcomes in cystic fibrosis: a center-based analysis

CONTEXT: Guidelines for managing cystic fibrosis (CF) patients have been widely circulated, but little is known about the variations in practice between sites and their association with outcomes. OBJECTIVE: To determine whether differences in lung health existed between groups of patients attending different CF care sites and to determine whether these differences are associated with differences in monitoring and intervention. DESIGN: The analysis was conducted using data from the Epidemiologic Study of Cystic Fibrosis from 1995 through 1996. SETTING: This was an observational database collecting prospective information from a large number of CF patients undergoing routine care in North America. PARTICIPANTS: Participating sites that had at least 50 CF patients who had each made at least one visit to a center during the 2-year study period were ranked on the basis of median values for FEV(1) within each of three age groups (6 to 12 years, 13 to 17 years, and >or= 18 years). INTERVENTIONS: There were no prespecified interventions in this observational study. MAIN OUTCOME MEASURES: The frequency of patient monitoring and the use of therapeutic interventions were compared between sites in the upper and lower quartiles after stratification within the site for disease severity. RESULTS: Within-site rankings tended to be consistent across the three age groups. Patients who were treated at higher ranking sites had more frequent monitoring of their clinical status, measurements of lung function, and cultures for respiratory pathogens. These patients also received more interventions, particularly IV antibiotics for pulmonary exacerbations. CONCLUSION: We found substantial differences in lung health across different CF care sites. We found that frequent monitoring and increased use of appropriate medications in the management of CF are associated with improved outcomes.