Does high-normal blood pressure lead to excess cardiovascular disease events and deaths in Chinese people? A post-hoc analysis of the 30-year follow-up of the Da Qing IGT and Diabetes Study

Aim: Whether systolic/diastolic blood pressure (SBP/DBP) values of 130-139/80-89 mmHg should be defined as hypertension has been debated for decades. We aimed to characterize the effect of high-normal BP on cardiovascular disease (CVD) events and deaths.

Methods: In total, 1726 individuals from the original Da Qing IGT and Diabetes Study were enrolled, and divided into the normal BP group (SBP <130 mmHg and DBP <80 mmHg), high-normal BP group (SBP 130-139 mmHg and/or DBP 80-89 mmHg) and hypertension group (SBP ≥140 mmHg and/or DBP ≥90 mmHg). CVD events and their components were assessed from 1986 to 2016.

Results: During the 30-year follow-up, the high-normal BP group was not at higher risk for CVD events [hazard ratio (HR) 1.05, 95% confidence interval (CI) 0.84-1.30, p = .68], coronary heart disease (HR 1.12, 95% CI 0.77-1.63, p = .57), stroke (HR 1.05, 95% CI 0.82-1.34, p = .71), or CVD deaths (HR 1.15, 95% CI 0.82-1.60, p = .41) compared with the normal BP group, after adjusting for covariates. However, the hypertension group exhibited significantly increased cardiovascular risk (CVD events, HR 1.91, 95% CI 1.48-2.46, p < .0001; coronary heart disease, HR 1.73, 95% CI 1.12-2.67, p = .01; stroke, HR 1.90, 95% CI 1.43-2.52, p < .0001; CVD deaths, HR 2.07, 95% CI 1.43-3.01, p = .0001) than the normal BP group. Subgroup analyses showed that, regardless of the presence of diabetes, high-normal BP did not increase CVD events compared with normal BP.

Conclusions: This post-hoc study provided no evidence that the high-normal BP increased cardiovascular risk in the Da Qing study population, suggesting that it was reasonable to continue to define hypertension at 140/90 mmHg in China.