The DRI to predict 4-year OS was calculated using Cox proportional hazard models, which included the following variables: age, sex of the donor and recipient, donor type, HLA match, graft source, CMV serostatus of donor and recipient, GVHD prophylaxis, therapy-related AML, FLT3 ITD status for AML, year of transplantation, and whether the transplant was performed on a clinical trial. Here, FLT3 is linked to acute myeloid leukemia.