Early Post-Transplantation Spirometry Is Associated with the Development of Bronchiolitis Obliterans Syndrome after Allogeneic Hematopoietic Cell Transplantation.

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 transplantation may offer improved strategies for early detection that could avert the morbidity and mortality of BOS. This study aimed to determine whether a decline in lung function before and early after (days +80 to +100) allo-HCT are associated with a risk of BOS beyond 6 months post-transplantation. In a single-center cohort of 2941 allo-HCT recipients, 186 (6%) met National Institutes of Health criteria for BOS. Pretransplantation and post-transplantation day +80 spirometric parameters were analyzed as continuous variables and included in a multivariable model with other factors, including donor source, graft source, conditioning regimen, use of total body irradiation, and immunoglobulin levels. Pre-transplantation forced expiratory flow between 25% and 75% of maximum (FEF25-75), day +80 forced expiratory volume in 1 second (FEV1), and day +80 FEF25-75 had the strongest associations with increased risk of BOS. Assessment of the multivariable model showed that a decline in day +80 FEF25-75 added additional risk to the day +80 FEV1 model (P = .03), whereas FEV1 decline at day +80 added no additional risk to the day +80 FEF25-75 model (P = .645). Moreover, day +80 FEF25-75 conferred additional risk when considered with pretransplantation 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 post-transplantation pulmonary function tests for the potential risk stratification of patients at risk for BOS.