European Respiratory Review (Jun 2008)
The effect of baseline lung function on the determination of time to bronchiolitis obliterans syndrome
Abstract
Long term survival after lung transplantation depends on the development and severity of bronchiolitis obliterans syndrome (BOS). The objective of this study was to identify the relationship between baseline FEV1 and transplant procedure type, on the development and progression of BOS grade 0p to 3. All patients receiving a cadaveric lung transplant 1992-2004 were included in the study (n = 389). Exclusion criteria were patients surviving <3 months (n = 39) and missing spirometry measurements (n = 4). There were significant differences between the transplant procedures, heart-lung (HLTx), double-lung (DLTx), and single-lung (SLTx), with respect to recipient age, BMI, and indication for transplantation. Baseline FEV1 for HLTx (median 2.9L, quartiles 2.3–4.3L) and DLTx recipients (median 2.9L, quartiles 2.4–3.7L) were significantly larger than for patients undergoing SLTx procedures (median 1.6L, quartiles 1.3–1.9L), p<0.0001, respectively. Survival analyses demonstrated a significant association between baseline FEV1 per litre and the development of BOS: grade 0p (HR: 0.59, CI: 0.51–0.68, p<0.0001); grade 1 (HR: 0.60, CI: 0.51–0.70. p<0.0001); grade 2 (HR: 0.62, CI 0.52–0.74, p<0.0001); and grade 3 (HR: 0.73, CI 0.60–0.89, p = 0.002). There was a significant log-log linear relationship between baseline FEV1 and time to the development of BOS grades 0p to 3 in all patients developing the respective BOS grade (p<0.0001, respectively). Baseline lung function is an important confounder and should be considered in future risk factor evaluations for the development and progression to BOS.