Epidemiology, Risk Factors, and Outcomes of Diffuse Alveolar Hemorrhage After Hematopoietic Stem Cell Transplantation.

BACKGROUND: Diffuse alveolar hemorrhage (DAH) is an uncommon complication of hematopoietic stem cell transplantation (HCT) that carries high morbidity and mortality. Limited contemporary data are available regarding the incidence, outcomes, and risk factors for DAH. RESEARCH QUESTION: What are the incidence, outcomes, and risk factors for DAH developing after HCT? METHODS: This was a single-center retrospective cohort study of patients who underwent HCT between January 1, 2005, and December 31, 2016. The incidence and outcomes of DAH development were evaluated. A multivariate logistic regression model was used to analyze differences between survivors and nonsurvivors. RESULTS: Of 4,350 patients undergoing first-time HCT, DAH was diagnosed in 99 (2.3%). DAH was seen in 40 of 3,536 autologous HCT recipients (1.1%) and 59 of 814 allogeneic HCT recipients (7.2%). Mean age was 53 ± 13 years, and median time of DAH diagnosis was 126 days (interquartile range, 19-349 days) after HCT. In-hospital mortality and mortality 1 year after DAH diagnosis were 55.6% and 76.8%, respectively. DAH diagnosis more than 30 days after transplantation (OR, 7.06; 95% CI, 1.65-30.14), low platelet count (OR, 0.98; 95% CI, 0.96-1.0; P = .02), elevated international normalized ratio (INR; OR, 4.08; 95% CI, 0.64-25.88; P = .046) and need for invasive mechanical ventilation (OR, 8.18; 95% CI, 1.9-35.21) were associated with higher in-hospital mortality. Steroid treatment did not alter mortality (P = .80) or length of stay (P = .65). However, among those who received steroids, survival was higher in whose who received modest-dose steroids (< 250 mg methylprednisolone equivalent/d) compared with those who received high-dose steroids (≥ 250 mg methylprednisolone equivalent/d; OR, 0.21; 95% CI, 0.07-0.72). INTERPRETATION: The mortality of DAH after HCT remains high, and DAH can occur long after transplantation. Later development of DAH (>30 days after HCT), need for invasive mechanical ventilation, thrombocytopenia, and elevated INR are all associated with worse outcomes.