Abstract

Background: In India, cardiovascular events are often diagnosed at lower blood pressures (BP) than in Western countries, questioning whether the actual World Health Organization (WHO) cut-off points for hypertension (systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg) are appropriate in low-resource countries.

Methods: A large population-based cohort study including 167 331 adults aged 35 to 90, living in a rural area, was followed-up during a 7-year mean duration for all-cause mortality and cardiovascular diseases (CVD) deaths. At baseline, casual BP was measured and lifestyle was assessed through a questionnaire. Mortality rates were calculated according to the systolic and diastolic BP, and their association was examined in a multivariate analysis, among all subjects, stratified by sex and age-groups.

Results: Forty-five percent of the study subjects had hypertension. The nadir of CVD mortality rates was observed at 110 mmHg for casual systolic BP and 75-80 mmHg for casual diastolic BP. In the multivariate analysis, risks of all-cause mortality, ischemic heart disease and stroke increased significantly from systolic BP of 140 mmHg and diastolic BP of 100 mmHg. High systolic and diastolic BP values were greater predictors of mortality in the young age-group (34-44) than in the old age-group (65+). Systolic BP was a stronger independent predictor of CVD than diastolic BP.

Conclusions: The findings of our study are consistent with the current WHO recommendations for hypertension definition. Measurement limited to systolic BP alone would be effective in screening for hypertension in large populations.