Lung function decline in cystic fibrosis patients and timing for lung transplantation referral

Study objectives: To determine risk factors associated with an accelerated decline in lung function in cystic fibrosis (CF), and whether longitudinal changes in FEV₁ would be a better predictor of the need for referral for lung transplantation than any single value for FEV₁. Design: The rate of decline in pulmonary function was determined by standard linear regression from each patient's calendar year's best percentage of predicted FEV₁ (%FEV₁) over at least 4 years, and patients were classified into three cohorts based on their rate of decline. Differences between groups in age, weight-for-age z score, gender, genotype, pancreatic status, diabetes, and the presence of various lung microbial isolates were analyzed. A subset of 30 patients referred for lung transplantation were further analyzed, and a prediction model for lung transplantation referral was created using the patient's rate of decline in lung function, the mean waiting time for donor organs, and the average level of lung function of patients prior to lung transplantation. Patients: One hundred fifty-three patients with CF followed up at the Washington University Adult Cystic Fibrosis Center. Results: Younger age, malnutrition, and concurrent infection with both Pseudomonas aeruginosa and Staphylococcus aureus were significant (p < 0.05) risk factors for rapidly declining lung function. Among patients with rapidly declining lung function, referral for lung transplantation would have occurred 8.4 months earlier than actual referral age (p < 0.05) if the prediction model had been used, possibly resulting in additional patient salvage in several cases. Conclusions: Rate of decline in lung function should be routinely evaluated in patients with CF, and a prediction model utilizing the rate of decline in %FEV₁, and the median regional waiting period for donor lungs for patients with CF may assist in the timing of referral for lung transplantation and more rapidly declining lung function.