Clinical presentation of multiple myeloma by race/ethnicity and Asian subgroup in an integrated healthcare system.

Abstract

e20012 Background: Several US studies have evaluated ethnic differences in patients with multiple myeloma (MM), but few have focused on populations other than non-Hispanic Whites and Blacks. We examined ethnic differences in a contemporary cohort of MM patients and their presenting laboratory findings in a large, insured, community-based population, including findings across Asian American subgroups. Methods: Using the Kaiser Permanente Northern California (KPNC) Cancer Registry, we identified all new cases of MM from 2010-2018 and obtained data on age, sex, race/ethnicity, Asian subgroup, and presenting hemoglobin, calcium, and estimated renal function (eGFR derived from serum creatinine) from health plan databases. Moderate to severe anemia was defined by hemoglobin <10 g/dL, hypercalcemia by calcium >11 mg/dL, and chronic kidney disease (CKD) by eGFR: stage 3 (eGFR 30-59) and stages 4-5 (eGFR <30). MM incidence was estimated using membership denominators. Results: There were 2224 new MM cases (mean age 68y, 60% male) in 2010-2018, with an annual MM incidence of 7.9-9.8/100,000. Table 1 compares presentation by race/ethnicity. Non-Whites (45%) were more likely to present at age <65 than non-Hispanic Whites (30%, p<0.01). Black (43%) and Asian (39%) adults were more likely to present with hemoglobin <10 g/dL than non-Hispanic Whites (27%, p<0.01); Black adults were more likely to present with hemoglobin <10 g/dL than Hispanic adults (31%, p=0.02). Among the primary Asian subgroups, proportions with hemoglobin <10 g/dL were 38% (East Asian), 43% (Filipino), and 45% (South Asian). Blacks were more likely to present with CKD stage 4-5 (19.5%) than other races/ethnicities (p=0.04); differences between White vs non-White or Asian vs non-Asian were not significant. In Asians, 12.7% (South Asian) and 19.0% (Filipino, East Asian) presented with CKD 4-5. Asians were least likely to present with hypercalcemia (6.7%, p=0.03), and this was similar for Asian subgroups. Conclusions: We observed ethnic differences in MM presentation in a large integrated healthcare system. Blacks were more likely to have CKD stage 4-5 and hemoglobin <10 g/dL than non-Hispanic Whites. Asians were more likely to have CKD stage 4-5 than non-Hispanic Whites but least likely to have hypercalcemia. This is one of the first studies to identify Asian subgroups and examine variation across East Asians, Filipinos, and South Asians. Analyses examining ethnic differences in survival among MM patients are in progress.[Table: see text]