Course of FEV1 after Onset of Bronchiolitis Obliterans Syndrome in Lung Transplant Recipients

Abstract

Rationale: Bronchiolitis obliterans syndrome (BOS), defined by loss of lung function, develops in the majority of lung transplant recipients. However, there is a paucity of information on the subsequent course of lung function in these patients. Objectives: To characterize the course of FEV1 over time after development of BOS and to determine the predictors that influence the rate of functional decline of FEV1. Methods: FEV1% predicted (FEV1%pred) trajectories were studied in 111 lung transplant recipients with BOS by multivariate, linear, mixed-effects statistical models. Measurements and Main Results: FEV1%pred varied over time after BOS onset, with the steepest decline typically seen in the first 6 months (12% decline; p < 0.0001). Bilateral lung transplant recipients had significantly higher FEV1%pred at BOS diagnosis (71 vs. 47%; p < 0.0001) and at 24 months after BOS onset (58 vs. 41%; p = 0.0001). Female gender and pretransplant diagnosis of idiopathic pulmonary fibrosis were associated with a steeper decline in FEV1%pred in the first 6 months after BOS diagnosis (p = 0.02 and 0.04, respectively). A fall in FEV1 greater than 20% in the 6 months preceding BOS (termed “rapid onset”) was associated with shorter time to BOS onset (p = 0.01), lower FEV1%pred at BOS onset (p < 0.0001), steeper decline in the first 6 months (p = 0.03), and lower FEV1%pred at 2 years after onset (p = 0.0002). Conclusions: Rapid onset of BOS, female gender, pretransplant diagnosis of idiopathic pulmonary fibrosis, and single-lung transplantation are associated with worse pulmonary function after BOS onset.