Influence of body mass index on survival in veterans with multiple myeloma

Purpose. We investigated the association between body mass index (BMI) at the time of multiple myeloma (MM) diagnosis and overall survival in a cohort of patients within the Veterans Health Administration system. We also evaluated the association between weight loss in the year prior to diagnosis and survival. Patients and Methods. Prospective analysis was performed on a retrospectively assembled cohort of 2,968 U.S. veterans diagnosed and treated for MM between September 1, 1999, and September 30, 2009, with follow-up information through October 22, 2011. Cox modeling controlling for patient- and disease-related prognostic variables was used to analyze the data. Results. Underweight patients (BMI <18.5 kg/m²) had increased mortality, whereas patients who were overweight (BMI 25-29.9 kg/m²) and obese (BMI ≥30 kg/m²) had lower mortality compared with healthy-weight patients (BMI 18.5-24.9 kg/m²). Weight loss ≥10% of baseline in the year before diagnosis was also associated with increased mortality and made the association between increased BMI and survival nonsignificant. Conclusion. Disease-related weight loss may be an important and heretofore unknown indicator of poor prognosis in MM. Assessment of weight loss prior to MM diagnosis should become a standard component of the clinical history in patients with newly diagnosed MM. Further research may identify relationships between disease-related weight loss and currently used prognostic factors in MM, further defining the role of this clinical factor in prognostic stratification.