The role of obesity in prognosis of acute myeloid leukemia (AML) is debatable. Our retrospective study aimed to determine the effect of obesity on overall survival (OS) in AML.

AML patients diagnosed at University of Nebraska Medical Center were divided into 3 groups according to body mass index (BMI): normal (18.5-25 kg/m²) or underweight (< 18.5 kg/m²); overweight (25-30 kg/m²); and obese (≥ 30 kg/m²). Chi-square test, Kruskal-Wallis test, and ANOVA were used to examine the association of BMI with baseline characteristics. Mann-Whitney test was used for pairwise comparisons of hematopoietic cell transplantation (HCT) comorbidity index. Bonferroni correction was used to adjust P values. OS, defined as time from diagnosis to death from any cause, was determined by the Kaplan-Meier method; comparisons of survival curves were done using log-rank test. Cox regression analysis was performed to detect the effect of BMI on OS.

Of 314 patients, 38% were obese, 68% received intensive chemotherapy, and 30% underwent HCT. Patient characteristics for all BMI groups were similar except greater HCT comorbidity index in obese patients. Actual body weight was used to calculate the chemotherapy dose in 92% of obese patients. The rates of receipt of HCT in normal, overweight, and obese groups were 33%, 32%, and 25%, respectively (P = .6). One-year OS values for normal/underweight, overweight, and obese groups was 42%, 45%, and 39%, respectively (P = .31). On multivariate analysis, obesity was associated with worse OS compared to normal-weight (hazard ratio = 0.6; 95% confidence interval, 0.4-0.9; P = .03) but not overweight patients.

Obesity confers worse prognosis in AML. Differences in OS were not the result of differences in chemotherapy dose or receipt of HCT.