SEX-SPECIFIC BLOOD PRESSURE CUT-OFFS ASSOCIATED WITH CARDIOVASCULAR EVENTS: A REAL-WORLD COHORT STUDY OF 1,931,155 CHINESE INDIVIDUALS

Objective: Cardiovascular disease (CVD) is the leading cause of death. Elevated systolic blood pressure (SBP) is the main modifiable risk factor and is more closely linked to CVD in women than in men. In Western populations, CVD occurs at lower SBP levels in women, suggesting a lower diagnostic and treatment cutoffs. However, sex-specific differences in other populations such as Chinese have not been reported. This study aims to explore the association between blood pressure (BP) and CVD in a general Chinese population using data from the Hong Kong Hospital Authority. Design and method: This retrospective cohort study included 1,931,155 patients (1,113,662 women and 817,493 men) who visited public health services from 1997 to 2021. Patients with a history of CVD, those under 18, and those with extreme BP (SBP/DBP>=250/140 or <70/40 mmHg) readings were excluded. The primary outcome was a composite CVD event, including CVD mortality, non-fatal coronary heart disease, heart failure, and stroke. We used sex-stratified, multivariable-adjusted accelerated failure time models to examine the association between SBP categories (defined by 10 mmHg increment from <110 to >=160) and CVD outcomes. Results: Over a median follow-up of 9.2 years, 146,249 women and 152,120 men experienced a CVD event. Figure 1 summarises our analysis. Compared to SBP<110 mmHg, the median time to CVD events was significantly decreased in all higher SBP categories among both men and women. In men, the time ratio (TR) ranged from 0.96 for SBP 110-119 to 0.69 for SBP>=160; In women, TR ranged from 0.86 for SBP 110-119 to 0.66 for SBP>=160. In particular, the magnitude of TR observed in women (TR: 0.86 [0.84-0.89]) with SBP 110-119 was comparable to that observed in men with SBP 130-139 (TR: 0.87 [0.84-0.90]). Conclusions: CVD risk rises steeply starting at a lower SBP level in Chinese women (110-119 mmHg) and CVD risk associated with SBP of 130-140mmHg in men is comparable to that of an SBP of 110-120mmHg in women, suggesting a lower diagnostic and treatment thresholds for women, comparable to studies in Western studies and require further investigation.