Early posttransplant spirometry is associated with the development of bronchiolitis obliterans syndrome after allogeneic hematopoietic cell transplant.

Abstract

Bronchiolitis obliterans syndrome (BOS) after allogeneic hematopoietic cell transplantation (allo-HCT) is often diagnosed at a late stage when lung dysfunction is severe and irreversible. Identifying patients early after transplant may offer improved strategies for early detection that could avert the morbidity and mortality of BOS. This study aimed to determine if decline in lung function pre and early post-transplant (days +80-100) are associated with risk of BOS at least 6 months after transplant. In a single center cohort of 2941 allo-HCT recipients, 186 (6%) met NIH criteria for BOS. Pre-transplant and day +80 spirometric parameters were analyzed as continuous variables and included in a multivariable model with other factors such as donor source, graft source, conditioning regimen, use of total body irradiation and immunoglobulin levels. Pre-transplant FEF25-75 (forced expiratory flow between 25-75% maximum), day +80 FEV1 (forced expiratory volume in 1 sec) and day +80 FEF25-75 had the strongest association with increased risk of BOS. Assessment of the multivariable model showed that day +80 FEF25-75 decline added additional risk to the day +80 FEV1 model (p=0.03), while FEV1 decline at day +80 added no additional risk to the day +80 FEF25-75 model (p=0.645). Moreover, day +80 FEF25-75 conferred additional risk when considered with pre-transplant FEF25-75. These results suggest that day +80 FEF25-75 may be more important than FEV1 in predicting the development of BOS. This study highlights the importance of obtaining early posttransplant pulmonary function tests for the potential risk stratification of patients at risk for BOS.