The effect of race and co-morbidities on Alzheimer's disease based on Medicare data

Introduction Alzheimer's disease (AD) incidence is thought to be higher among Black than White individuals. Methods We studied the US Medicare population from 2000 to 2018. Cox regression was used to determine the roles of race and co-morbidities for AD incidence. Results We studied 11,880,906 Medicare beneficiaries, with 774,548 AD cases. Hazard ratios (HRs) by increasing numbers of co-morbidities (1-7) were 1.51, 2.00, 2.55, 3.16, 2.89, 4.77, and 5.65. Among those with no co-morbidities, Black individuals had a lower rate than those who are White (HR = 0.69), while among those with one more co-morbidities, Black individuals had a higher rate (HR = 1.19). The presence of hypertension increased AD rates by 14% for White individuals, but 69% for those who are Black. Discussion More co-morbidities was strongly associated with higher AD rates. The higher rates for Black versus White individuals was apparent only for those with co-morbidities and appears driven both by more co-morbidities, and the greater effect of hypertension. Highlights Black individuals have been shown to have higher Alzheimer's disease (AD) rates than those who are White. Some co-morbidities are known to increase AD risk. Among those In Medicare data with no co-morbidities, Black individuals have less risk than those who are White. Among those with co-morbidities, Black individuals have higher rates than those who are White. Hypertension results in a much stronger increase in AD risk for Black versus White individuals.

Automated summary

This study reveals that Black individuals have a higher incidence of Alzheimer's disease (AD) compared to White individuals. The presence of more co-morbidities is strongly associated with an increased risk of AD. Furthermore, hypertension has a greater impact on AD risk among Black individuals.