Obesity may have a distinct influence on allogeneic hematopoietic cell transplantation results with various donor types. For a study, researchers presented the findings of registry research comparing the outcomes of alternative donors (haploidentical related donor with two or more mismatches and receiving post-transplant cyclophosphamide [haplo] and cord blood (CBU)) to matched unrelated donors (MUD). Adult patients receiving MUD (n=11,801), haplo (n=2,894), and CBU (n=1,487) for hematologic malignancy (2013–2017) (N=16,182) were included. The primary outcome was non-relapse mortality (NRM). The study revealed a significant, non-linear interaction between pretransplant BMI and the three donor groups for NRM: NRM risk was considerably greater with CBU than haplo at BMI 25–30 [hazard ratio (HR) 1.66–1.71, P<0.05] and MUD transplants at BMI 25–45 (HR, 1.61–3.47, P<0.05). 

The findings showed that NRM and survival outcomes are poorer in overweight and obese transplant patients (BMI≥25) with one alternative donor type against MUD, however, obesity did not appear to give a uniform difference in mortality risk with one donor type over the other. If a matched sibling donor is not available, BMI may be used as a factor for choosing a donor among the three possibilities (MUD, haplo, and CBU).