Ethnic Differences in Cardiac Rehabilitation Enrolment, Participation, and Mortality: A Retrospective Cohort Study from Auckland, New Zealand

Background/Objectives: Ethnic inequities in cardiovascular disease and healthcare access are well recognised worldwide, but it is unclear whether these inequities translate into differences in cardiac rehabilitation participation and subsequent clinical outcomes. This study examined ethnic differences in cardiac rehabilitation enrolment, participation, and mortality outcomes within a large multi-ethnic cohort to determine whether the association between rehabilitation exposure and mortality differed across ethnic groups. Methods: This retrospective cohort study included 4940 consecutive patients referred to the Auckland cardiac rehabilitation programme between 2016 and 2023. Baseline characteristics, rehabilitation participation, and all-cause mortality were examined across ethnic groups. Associations with mortality were assessed using multivariable Cox proportional hazards models adjusted for demographic and clinical risk factors. Results: During a median follow-up of 5.6 years, 565 deaths occurred. Cardiac rehabilitation participation differed across ethnic groups (p < 0.001), with lowest participation among Pacific patients (44.3%) and highest participation among Asian patients (58.6%). Among attenders, total session attendance was similar across ethnic groups (p = 0.35). After adjustment, mortality risk was lower among Asian patients (HR 0.58, 95% CI 0.46–0.74, p < 0.001), but did not differ for Māori (HR 1.21, 95% CI 0.86–1.71) or Pacific patients (HR 1.03, 95% CI 0.79–1.36) compared with Europeans. Greater rehabilitation exposure was associated with lower mortality (HR 0.98 per session, 95% CI 0.97–0.99, p = 0.002), and no interaction between ethnicity and rehabilitation exposure was observed. Conclusions: Ethnic differences in cardiac rehabilitation were evident at the level of enrolment, but not in session exposure among attenders or in the association between rehabilitation participation and mortality. This study highlights the importance of distinguishing inequities in access and engagement from the effectiveness of rehabilitation once delivered.