Risk Factors for Waiting List Mortality in Lung Transplant Candidates With Post‐Hematopoietic Stem Cell Transplantation Non‐Infectious Pulmonary Complications

Background: Late-onset non-infectious pulmonary complications (LONIPCs) following hematopoietic stem cell transplantation (HSCT) are a known indication for need of lung transplantation. This study aimed to clarify the clinical characteristics of patients with LONIPCs after HSCT who were registered for lung transplantation and reveal the risk factors for waiting list mortality.
Methods: We retrospectively reviewed the clinical data of patients with LONIPCs after allogeneic HSCT who were referred to Okayama University Hospital and registered in the Japan Organ Transplant Network for deceased-donor lung transplantation between 2005 and 2023. Pediatric patients aged <18 years at the time of registration were excluded.
Results: Thirty-four patients were included in this study. Notably, two distinct phenotypic groups were identified: One with a bronchiolitis obliterans pattern on high-resolution computed tomography and a mixed ventilatory defect, and the other with a pleuroparenchymal fibroelastosis pattern and a restrictive ventilatory defect. The median waiting duration for a deceased-donor lung transplant was 662 days, and 16 patients died during the waiting period. The cumulative incidence of waiting list mortality was 20.6% (95% confidence interval [CI], 8.9%–35.6%) at 1 year and 46.1% (95% CI, 27.8%–62.7%) at 3 years. A history of pneumothorax, greater dyspnea on exertion, and higher serum Krebs von den Lungen-6 levels were associated with an increased risk of waiting list mortality.
Conclusion: In patients with LONIPCs after HSCT, a history of pneumothorax may be a marker of a poor prognosis and could serve as a criterion for referral of lung transplantation.