The predictive value of pulmonary function test before transplantation for chronic pulmonary graft-versus-host-disease after allogeneic hematopoietic stem cell transplantation

Background: Pulmonary chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a devastating complication and often diagnosed at a late stage when lung dysfunction is irreversible. Identifying patients before transplant who are at risk may offer improved strategies to decrease the mortality. Bronchiolitis obliterans syndrome (BOS) is the typical manifestation of pulmonary cGVHD, which is clinically diagnosed by pulmonary function test (PFT). This study aimed to evaluate the predictive value of PFT pre-HSCT for BOS. Methods: A single center cohort of 923 allo-HSCT recipients was analyzed, including 15 patients who developed pulmonary cGVHD. Kaplan-Meier method was used to analyze the 3 year progression free survival and 3 year overall survival (OS). A Cox regression model was applied for univariate and multivariate models. Results: The 3 year cumulative incidence of pulmonary cGVHD was 2.04% (95% CI 1.00-3.08%). According to the cut-off values determined by receiver operator characteristic curve, higher ratio of forced expiratory volume during one second to forced vital capacity (FEV1/FVC) pre-HSCT was correlated to a lower incidence of pulmonary cGVHD [0.91% (95% CI 0.01-1.81%) vs. 3.61% (95% CI 1.30-5.92%), P < 0.01], and so as peak expiratory flow to predictive value (PEF/pred) [0.72% (95% CI 0-1.54%) vs. 3.74% (95% CI 1.47-6.01%), P < 0.01]. Multivariate analysis showed that FEV1/FVC (HR = 3.383, P = 0.047) and PEF/pred (HR = 4.426, P = 0.027) were independent risk factors for onset of BOS. Higher FEV1/FVC and PEF/pred level were related to a significantly decreased 3 year non-relapse mortality. The 3 year OS was superior in patients with higher PEF/pred [78.17% (95% CI 74.50-81.84%) vs. 71.14% (95% CI 66.08-76.20%), P = 0.01], while FEV1/FVC did not show significance difference. Conclusion: Our results suggested that PFT parameters such as PEF/pred and FEV1/FVC could be predictors for pulmonary cGVHD and even transplant outcomes before HSCT.