Hospitalization risk with and without dementia by region and race in the United States.

Understanding regional and racial variation in the risk of hospitalization with Alzheimer's disease and related dementias (ADRD)-and how it differs from other conditions-is required to inform effective practice and policy. However, no prior studies have simultaneously estimated county-level regional and race-specific variation in hospitalization risk. We assessed hospitalizations with and without ADRD diagnoses among Black and White Medicare Fee-for-Service beneficiaries from 2000 to 2018 and used Bayesian shared component models to estimate geographic variation in hospitalizations jointly for both racial groups. We decomposed hospitalization risk across 3037 counties into (1) risk shared by all beneficiaries and (2) risk specific to either Black or White beneficiaries. We analyzed 143 891 769 hospitalizations (13.2% with ADRD). For hospitalization with ADRD, shared risk was elevated in southern and eastern states; Black-specific risk was elevated in the Midwest, Florida, and California; and White-specific risk was elevated in Appalachia. Black relative risk was significantly higher than White relative risk in 90.2% (2740/3037) of counties for hospitalization with ADRD and 44.7% (1359/3037) of counties for hospitalization without ADRD. These findings underscore the importance of considering regional differences in race-specific risk when assessing hospitalization disparities.