Decrease of lethal infectious complications in the context of causes of death (COD) after hematopoietic cell transplantation: COD-2 and COD-1 study of the Infectious Diseases Working Party EBMT.

We previously analyzed trends in incidence and factors associated with lethal complications in ALL/AML/CML patients (causes of deaths; COD-1 study). The objective of this study was the analysis of incidence and specific causes of death after HCT, with focus on infectious deaths in two time periods, 1980-2001 (cohort-1) and 2002-2015 (cohort-2). All patients with HCT for lymphoma, plasma cell disorders, chronic leukemia (except CML), myelodysplastic/myeloproliferative disorders, registered in the EBMT-ProMISe-database were included (n = 232,618) (COD-2 study). Results were compared to those in the ALL/AML/CML COD-1 study. Mortality from bacterial, viral, fungal, and parasitic infections decreased in very early, early and intermediate phases. In the late phase, mortality from bacterial infections increased, while mortality from fungal, viral, or unknown infectious etiology did not change. This pattern was similar for allo- and auto-HCT in COD-1 and COD-2 studies, with a distinct and constant lower incidence of all types of infections at all phases, after auto-HCT. In conclusion, infections were the main cause of death before day +100, followed by relapse. Mortality from infectious deaths significantly decreased, except late phase. Post-transplant mortality has significantly decreased in all phases, from all causes after auto-HCT; it has decreased in all phases after allo-HCT except late phase.