Abstract TH190: Ethnic Disparities in All-Cause and Cardiovascular Mortality Among Hypertensive Patients: Findings from a Multi-Ethnic Cohort Study in China

Background: Studies in Western countries showed significant racial and ethnic differences in hypertension and cardiovascular adverse outcomes. However, in China, this information is lacking. This study aimed to characterize ethnic disparities in the risk of all-cause and cardiovascular disease (CVD) mortality among hypertensive patients and to quantify the relative contribution of various social determinants of health. Methods: This cohort study encompassed 55,940 hypertensive patients aged ≥35 years, including Han, Yi, Zhuang, Dai, and Tibetan ethnic groups, who participated in the China Basic Public Health Service Program in 2018 and followed up until November 30, 2023. Differences in all-cause and CVD mortality between ethnic groups were analyzed using Cox proportional hazards regression models with adjustment for demographic (age and sex), socio-economic status (income, education), lifestyle, clinical risk factors, and residential altitude. The percent reduction in the β estimate (log-hazard ratio [HR]) for ethnic quantified the contribution of each factor group to ethnic differences in all-cause and CVD mortality. Findings: During a median of 5 years of follow-up, 12.3% of participants (n=6906) died, of which 7.8% (n=4337) died from CVD. After full model adjustment, the risk of for all-cause mortality increased by 50% (HR:1.50,1.37-1.63) and 42% (HR:1.42,1.13-1.79) for Dai, and Tibetan participants, respectively, compared with Han participants, while the risk of all-cause mortality was further reduced for Zhuang participants (HR:0.60,0.54-0.67), with no significant difference observed among Yi participants. Among Yi and Tibetan participants, adjusting for socioeconomic factors (108% and 137%) and altitude of residence (58% and 195%) resulted in the greatest reduction in β estimates for ethnicity. Similar trends were also seen for CVD mortality. Interpretation: The study highlights differences in all-cause and CVD mortality between different ethnic groups in Southwest China, which are contribution in part to social determinants of health and residential altitude. The findings support the need to identify and act on systemic factors that reduce health disparities between ethnic groups.