Abstract Rationale There is an increased risk of pulmonary dysfunction after hematopoietic stem cell transplant (HSCT) in the pediatric population, resulting in respiratory complications and mortality. As a part of TRANSPIRE (NCT04098445), an ongoing multi-center prospective observational cohort study, we aimed to characterize diffusing capacity of the lungs for carbon monoxide (DLCO) in children at pre-HSCT (baseline) and its longitudinal trend over 24 months. Methods TRANSPIRE is a multi-center prospective cohort study that evaluated baseline and longitudinal DLCO data at 8 centers: Cincinnati Children’s Hospital, University of Minnesota Masonic Children’s Hospital, Boston Children’s Hospital, Children’s Hospital of Philadelphia, Seattle Children’s Hospital, Texas Children’s Hospital, University of California San Francisco, and Denver Children’s Hospital. For this analysis, DLCO z-scores, generated from Global Lung Function Initiative equations, were analyzed using linear mixed model with time and diagnosis as fixed effects. Results A cohort of 714 children has been included in the analysis. Compared to baseline prior to HSCT, there is an initial decline of DLCO after HSCT at 60-day timepoint (p = 0.0005) that persists at 100-day timepoint (p = 0.000002), followed by uptrend at the 12-month mark similar to baseline (p = 0.14). At the 24-month timepoint, there is a significant increase in DLCO compared to baseline (p = 0.0000009). DLCO z-score trend is lower compared to spirometry and lung volume z-scores. Conclusion We present an overview of DLCO results in a cohort of children after HSCT. Initial results of our study suggest that there is an initial significant drop in DLCO, followed by a gradual rebound over time. Ultimately, there is a significant improvement at the 24-month timepoint compared to baseline (prior to HSCT). Lung injury and hemoglobin abnormalities may contribute to the differences. DLCO trend is worse than other standard lung function studies. Future research is needed to characterize longitudinal outcomes of DLCO and other lung functions after HSCT. This abstract is funded by: Transpire
Wong et al. (Fri,) studied this question.