Mortality Risk and Pulmonary Function in Adults With Cystic Fibrosis at Time of Wait Listing for Lung Transplantation

Abstract

Background: Lung transplantation (LTx) benefit for survival in cystic fibrosis (CF) patients placed on the wait list is not well studied.

Methods: To predict the relationship between initial forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) and the hazard ratio (HR) associated with LTx in CF patients, the United Network for Organ Sharing database was queried from 2005 to 2006 for adult patients with CF. Survival was assessed from wait list entry time until death on wait list, death after LTx, or censoring. Multivariate Cox proportional hazards models were used to assess the effect of LTx. The first model estimated the HR of LTx with adjustment for FEV1 or FVC and other covariates, and the second model estimated the HR of LTx conditional on FEV1 or FVC at listing.

Results: Two hundred seventy-eight patients with CF were included in the cohort, and 277 were used for survival analysis. Lung transplantation reduced the risk for death controlling for FEV1 (HR, 0.601; 95% confidence interval, 0.375 to 0.964; p = 0.035) or controlling for FVC (HR, 0.547; 95% confidence interval, 0.336 to 0.889; p = 0.015). Interaction models found that the HR of LTx varied significantly across initial FEV1 and FVC, with the predicted LTx HR and 95% confidence interval being protective (HR < 1) at FEV1 of 25% or less and FVC of 40% or less, respectively.

Conclusions: The benefit of LTx in adults with CF was significant at a lower baseline FEV1 than expected. A threshold for baseline FVC was established below which LTx was protective.