Background: Impact of obesity on transplant outcome is unknown. We hypothesized that obesity increases allogeneic transplant related morbidity/mortality. We therefore performed a case control study of obese patients with AML and MDS undergoing allogeneic transplant (AlloSCT) at our institution.

Patients and Methods: Sixty one patients with AML or MDS and a Body Mass Index (BMI) greater than 35 were transplanted from 1987 and 2006. 61 control patients were identified with BMI less than 30. The patients had similar characteristics. Controls were matched for age (within 5 years), disease status (relapse or remission), donor type (sib or MUD) and conditioning regimen.

Results: The median weight of obese patients was 109.5 Kg (range 78–151.3 Kg). Obese and controls had similar distribution of age (median age 47 years and 46 years respectively). Likewise gender, disease status, and cytogenetic risk groups were similar in the two groups. The majority (62%) of patients in both groups had IV Busulfan based conditioning therapy, while 11% had a TBI based regimen and 26% in both groups had reduced intensity conditioning with Fludarabine and Melphalan. Donor was a matched sib in 65% of cases and 66% of controls. The median time between transplant day and discharge was 23 days (range 14–98days) in both groups. Only significant difference between the two groups was the presence of comorbidites in obese patients. 75% of cases had a comorbidty score of 3 or more compared to 38% of controls (p<0.001) as defined by HCT index. Outcomes were similar in both groups. Two year non relapse mortality was 27% (95% CI: 18%-42%) in obese patients and 27% (95% CI: 17%- 41%) in control patients. Grade 3–4 toxicities occurred in 55% of cases compared to 42% of controls (p=0.2). Three-year disease free survival was 44% (95% CI: 31%- 57%) and 42% (95% CI: 29%- 55%) respectively in cases and controls. Median overall survival was 18 months for obese patients and 26 months for controls; 3-year overall survival was not significantly different in the two groups: 45% (95% CI: 31%- 58%) and 45% (95% CI: 31%- 58%) respectively for cases and controls.

Conclusion: Despite the higher prevalence of comorbidities in obese patients, obesity did not impair outcome in patients with AML/MDS undergoing AlloSCT. Hence, obesity should not be considered a contraindication to AlloSCT.

Disclosure: No relevant conflicts of interest to declare.