Racial and Ethnic Differences in Cardiac Rehabilitation Participation: Effect Modification by Household Income.

Background Cardiac rehabilitation (CR) is associated with improved cardiovascular outcomes. Racial and ethnic differences in CR have been identified, but whether income may attenuate these disparities remains unknown. We evaluated (1) racial/ethnic differences in CR participation in a contemporary sample of insured US adults, and (2) assessed how household income modifies associations between race or ethnicity and CR participation. Methods and Results We identified 107 199 individuals with a CR-qualifying diagnosis between January 1, 2016 and December 31, 2018 in Optum's de-identified Clinformatics database. We evaluated associations between race or ethnicity and participation in CR, and assessed interaction between race or ethnicity and annual household income. The mean±SD age of all participants was 70.4±11.6 years; 37.4% were female and 76.0% were White race. Overall, 28 443 (26.5%) attended ≥1 CR sessions. After adjustment, compared with White individuals, the probability of attending CR was 31% lower for Asian individuals (95% CI, 27%-36%), 19% lower for Black individuals (95% CI, 16%-22%), and 43% lower for Hispanic individuals (95% CI, 40%-45%), all <0.0001. The time to CR attendance was also significantly longer for Asian, Black, and Hispanic individuals. Associations between race or ethnicity and attendance at CR differed significantly across household income categories ( interaction=0.0005); however, Asian, Black, and Hispanic individuals were less likely to attend CR at all incomes. Conclusions In a geographically and racially diverse cohort, participation in CR was low overall, and was lowest among Asian, Black, and Hispanic candidates. Household income may impact the link between race or ethnicity and attendance at CR, but substantial racial and ethnic disparities exist across incomes.