Vitamin D Deficiency Predicts for Poor Overall Survival in Caucasian but Not African American Patients with Multiple Myeloma

Background: A number of studies have reported elevated incidence of 25-OH-vitamin D deficiency among patients with multiple myeloma (MM). Several studies have found association between vitamin D levels and factors associated with survival, including ISS stage at diagnosis. However, the impact of vitamin D deficiency on MM prognosis is not entirely clear. Also, in general, both the incidence and the impact of vitamin D deficiency differ substantially by race. Here, we investigate the impact of vitamin D deficiency on prognosis in a large and racially heterogenous patient population with MM in the Veterans Affairs (VA) system. Methods: We used the VA's nationwide Corporate Data Warehouse to identify patients diagnosed with symptomatic MM from 1999 to 2017. Various demographic and laboratory data was collected including age, race, 25-OH-vitamin D levels, and ISS stage at diagnosis as well as survival outcome data. Details of therapies received was also available which indicted similar access to all newer agents approved for myeloma for both African American (AA) and Caucasian patients. Results: We identified 15,717 patients diagnosed with MM (3353 AA and 9070 Caucasian), of whom 6675 had vitamin D measurements within 2 months of diagnosis (1959 AA and 4398 Caucasian). Median serum vitamin D levels were significantly lower among AA patients (21.8 ng/mL) than Caucasians (28.6 ng/mL; p