Nationwide study of COVID-19 outcomes in hematologic patients following bone marrow transplantation.

Background Patients with hematological malignancies (HMs), particularly those who have undergone bone marrow or hematopoietic stem cell transplantation (HSCT), are at greater risk for morbidity and mortality due to immunosuppression. The COVID-19 pandemic exacerbated these vulnerabilities in HM patients, although comprehensive data specifically on HSCT recipients are limited. Objective This study investigated the clinical and demographic profiles of HSCT recipients hospitalized with COVID-19 in Spain. We also identified factors associated with in-hospital mortality in HSCT patients. Methods We conducted a nationwide, retrospective analysis using data from the Spanish National Health System. We included hospitalized patients with HMs and COVID-19 infection from 2020 to 2022. We used descriptive statistics, multivariate logistic regression, and survival analyses to assess predictors of mortality. Results In total, 35,648 patients with HMs were included, of whom 2,324 (6.5%) had undergone HSCT. The in-hospital mortality rate for HSCT recipients was 13%, lower than the 20% observed in non-HSCT patients. Older age, dementia, acute leukemia, and solid tumors were independently associated with increased mortality. In spite of their immunosuppressed state, HSCT recipients experienced relatively favorable outcomes, suggesting partial immune recovery following transplantation. Conclusions HSCT recipients with COVID-19 present different clinical characteristics and mortality risks than non-recipients. These findings indicate the need for specific management strategies for this vulnerable population. Further research is needed to explore immunological recovery and the transplant-specific factors that may influence COVID-19 outcomes.