Geospatial analysis of the association of cardiometabolic diseases and incident Lewy body dementia in the Medicare population

INTRODUCTION: Research on the potential role of cardiometabolic diseases (CMDs) as risk factors for Lewy body dementia (LBD) is limited, and findings from existing studies remain inconclusive. We investigated the geospatial patterns of CMDs and the association with LBD across the United States (U.S.). METHODS We performed an observational case-control study using a nationwide, population-based Medicare dataset of 75,847 incident LBD and 379,235 controls from 2017 and 2018 and computed the odd ratios (ORs) and 95% confidence intervals (CIs) between eight CMDs and LBD, adjusted for age, sex, race, smoking, healthcare utilization, and area deprivation index. At the county-level, we computed and mapped the standardized incidence ratios (SIRs) of LBD. We then computed the standardized prevalence ratios (SPRs) for the CMDs that were positively associated with LBD to investigate the geospatial patterns of the association between these CMDs and LBD across the U.S. RESULTS Compared to controls, our LBD cases were older and male. Hispanic, non-Hispanic Black, and Asian/Pacific Islander beneficiaries had higher odds of LBD compared to the non-Hispanic White beneficiaries. Of the eight CMDs examined, stroke (OR = 1.99, 95% CI = 1.95–2.02) was positively associated with LBD risk, while the other CMDs were inversely associated with LBD risk. There was a substantial geographic variation of prevalent stroke and incident LBD across the U.S., with the highest spatial correlation in the South and Central Appalachia. DISCUSSION Stroke is associated with a higher LBD risk. We observed higher SIRs for LBD and SPRs for stroke among beneficiaries living in the Southern U.S.