Effects of systolic and diastolic blood pressures on incident coronary heart disease and all‐cause death in Chinese women with Type 2 diabetes: The Hong Kong Diabetes Registry

BACKGROUND: Elevated blood pressure (BP) is an important risk factor for the development of coronary heart disease (CHD), although the threshold above which the risk increases has not been clearly defined. The aim of the present study was to examine the full-range association between BP and CHD. METHODS: A prospective cohort of 3861 Chinese women with Type 2 diabetes mellitus (T2DM) was followed for a median of 5.61 years. Restricted cubic spline analysis was used to examine the relationship between BP and CHD. RESULTS: Subjects who developed CHD were older, more likely to be smokers, had a significantly longer duration of diabetes, higher systolic BP (SBP), glycated hemoglobin, albuminuria, low-density lipoprotein-cholesterol, and triglycerides, and lower estimated glomerular filtration rate and high-density lipoprotein-cholesterol. Mortality was higher in those who developed CHD compared with those who did not, with all-cause death in 30.2% and 7.8% of patients, respectively. Over 21,641 and 22 049 person-years follow up, 4.4% of patients (n = 169) developed CHD and 8.8% (n = 340) died, respectively. The relative risk of SBP for CHD was constant up to 120 mmHg, after which it started to rise: from 130 mmHg, each 10-mmHg increase in SBP was associated with a 1.13-fold increased risk of CHD. CONCLUSIONS: We identified 130 mmHg as the threshold of SBP for increased risk of CHD in Chinese female patients with T2DM. It appears that 67-77 mmHg is the optimal range for diastolic BP, within which the risk of CHD is lowest.