ATLANTA—Patients who lost 10% or more of their body weight in the year leading up to a diagnosis of multiple myeloma had a 58% greater risk of mortality, according to the first study to demonstrate this effect which was reported during the 54th American Society of Hematology Annual Meeting and Exposition.

“Elevated body mass index (BMI) has been associated with an increased risk of death from hematologic malignancies, including multiple myeloma,” said Kristen M. Sanfilippo, MD, of the Department of Medicine, Division of Oncology, Washington University School of Medicine, and Research Service, Saint Louis Veterans Administration (VA) Medical Center, Saint Louis, MO. “This occurs through modification of multiple myeloma disease incidence, survival after diagnosis, or a combination of the two.”

Of the 5,013 patients in the VA Hospitals Central Cancer Registry diagnosed with multiple myeloma between October 1998 and December 2009, 2,968 were included in the retrospective cohort analysis to evaluate the effect of BMI on survival patterns. Mean age was 68.2 years and the majority of the patients (98%) were male and white (71.4%). Mean Charlson comorbidity score was 2.6.

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Based on BMI at time of diagnosis, and controlling for age and comorbidities, a reduction in mortality was observed for patients who were overweight (BMI 25 to <30; n=1156; HR 0.82; 95% CI 0.75–0.91) and obese (BMI ≥30; n=755; HR 0.75; 95% CI: 0.67–0.84) compared to those of normal weight (BMI 18.5 to <25; n=972). Those underweight (BMI <18.5; n=85) had a higher mortality compared with patients of normal weight (HR 1.64; 95% CI 1.30–2.08).

To examine the potential confounder of disease-related weight loss, the investigators obtained weight information 1 year before diagnosis in a subset of the analytic cohort (n=1,983). Patients who had lost ≥10% of body weight over the year before diagnosis had higher mortality than those who did not (HR 1.52; 95% CI 1.34-1.72).

In addition, the association between obesity and decreased mortality was lost when analyzed by BMI 1 year before diagnosis (HR 0.93, 95% CI 0.81–1.07), and patients who were overweight had only borderline significance in mortality reduction (HR 0.87, 95% CI 0.76–0.99).

“The mechanisms by which disease related weight loss drives a poorer prognosis cannot be determined in a population-based study,” Dr. Sanfilippo concluded.