Trends in infection-related mortality among older adults with multiple myeloma in the United States over the last two decades.

e19553 Background: Multiple myeloma (MM) is associated with profound immune dysfunction and treatment-related immunosuppression, increasing susceptibility to infection-related mortality. However, national trends and demographic and geographic disparities in infection associated deaths among MM patients remain incompletely characterized. This study evaluated long-term mortality patterns from 1999 to 2023. Methods: CDC WONDER data was extracted using ICD-10 codes for MM (C90.0) and infectious causes including sepsis (A40–41), fungal infections (B35–49), pneumonia (J12–J18), and urinary tract infections (N39.0). Age-adjusted mortality rates (AAMR) per 1,000,000, standardized to the 2000 U.S. population, were calculated among adults aged ≥65 years. Temporal trends were assessed using Joinpoint regression from the year 1999 to 2023. Analyses were stratified by sex, race, states and place of death. Results: A total of 37,560 infection associated deaths occurred among MM patients. Most deaths occurred in medical facilities (77.8%), followed by nursing or long-term care facilities (7.7%). Overall AAMR decreased from 1999 to 2018, increased transiently during 2018 to 2021 (APC 3.63%), and then declined sharply to near pre-2018 levels. Among males, AAMR declined from 55.2 in 2004 to 40.9 in 2012 (APC −3.81%; p<0.05), followed by reversal with an increase to 42.3 in 2020. Female mortality demonstrated a sustained downward trend, decreasing from 31.4 in 2004 to 23.1 in 2011 (APC −3.37%; p<0.05) and further to 20.6 in 2023 without reversal. Across racial groups, Non-Hispanic Black populations consistently exhibited nearly double the AAMR compared with other groups. From 1999 to 2012, AAMR declined significantly among both Non- Hispanic Black (APC −3.02%; p<0.05) and Non-Hispanic White populations (APC −3.30%; p<0.05), followed by stabilization among Non-Hispanic Whites and a modest increase among Non-Hispanic Blacks. In contrast, Hispanic or Latino populations demonstrated a sustained decline from 1999–2023 (APC −1.29%;p < 0.05). State-level AAMRs varied widely, with rates in the District of Columbia nearly threefold higher than in Maine. Conclusions: Infection related mortality among older adults with MM declined during the early study period but demonstrated a subsequent resurgence, with marked racial and geographic disparities persisting. These findings highlight ongoing vulnerability among high-risk populations and underscore the need for targeted infection prevention strategies and improved access to supportive oncology care.