Impact of body mass index on the prognosis of patients with newly diagnosed multiple myeloma

Although obesity is an established modifiable risk factor for multiple myeloma (MM), the influence of obesity on survival among Black patients, among whom obesity and MM are more common, is less clear. We evaluated the association of body mass index (BMI) with progression free survival and overall survival among 834 histologically confirmed patients with newly diagnosed MM (NDMM) enrolled in the Integrative Molecular And Genetic Epidemiology study between 2009 and 2020. We estimated the association of BMI with the risk for progressed disease and all-cause and MM-specific mortality using hazard ratios (HR) and corresponding 95% confidence intervals (CI), calculated from multivariable Cox proportional hazard models adjusted for prognostic factors. When compared with NDMM patients with a normal BMI at diagnosis (18.5-24.9 kg/m2) positive associations with all-cause mortality were observed at the extremes with a 52% and 147% increased risk for death in patients with underweight (BMI, <18.5 kg/m2, HR, 1.52; 95% CI 0.48-4.84) and those with obesity (BMI, ≥30.0 kg/m2, HR, 2.47; 95% CI, 1.26-4.85), respectively. Patients with severe obesity (BMI, ≥35kg/m2) had the highest risk when compared with those with a normal BMI (HR, 3.14; 95% CI, 1.50-6.55), particularly among White (HR, 3.22; 95% CI, 1.30-7.94) and female (HR, 4.17; 95% CI, 1.20-14.47) patients with NDMM; however, the differences by race and sex were not statistically significant (Pinteraction ≥.60). Severe obesity was also associated with an 83% elevated risk for progressed disease among patients with NDMM (HR, 1.83; 95% CI, 1.04-3.24). These findings were similar for MM-specific mortality and highlight weight management as a potential strategy to improve the prognosis of all patients with NDMM.