[A prospective cohort study on blood pressure control and risk of ischemic stroke in patients with hypertension]

Objective: To explore the association between blood pressure control and risk of ischemic stroke (IS) in patients with hypertension. Methods: A total of 5 488 patients with hypertension from 60 communities were randomly selected from 101 communities in 8 streets of Nanshan District in Shenzhen City by using two-stage sampling method. The social demographic characteristics, behavior and life style, coronary heart disease and diabetes were collected and the physical condition, blood pressure and blood biochemical indexes were measured. From April 1, 2010 to August 31, 2017 as the follow-up period, the incidence of IS was annually collected by using telephone survey. Cox proportional hazard regression model was used to analyze the relationship between blood pressure control, systolic blood pressure (SBP), diastolic blood pressure (DBP) and the risk of IS. Results: The age of all patients was (58.50±12.14) years old, including 2 712 males (49.42%) and 3 112 patients with well-controlled blood pressure (56.71%). During the follow-up period, 358 new cases of IS were confirmed, and the incidence density was 1 346.27/100 000 person-years. Cox proportional hazard regression model analysis showed after adjusting for confounding factors, unstable blood pressure control, SBP≥150 mmHg (1 mmHg=0.133 kPa; compared with SBP<120 mmHg), and DBP≥95 mmHg (compared with DBP<80 mmHg) were associated with risk of IS. The HR (95%CI) was 1.29 (1.04, 1.59), 2.00 (1.26, 3.17) and 1.52 (1.01, 2.64), respectively. Subgroup analyses showed these associations only existed in female patients with hypertension. The HR (95%CI) was 1.39 (1.05, 1.85), 2.53 (1.41, 4.56) and 1.73 (1.00, 3.36), respectively. Conclusion: Unstable blood pressure control increases the risk of IS in female patients with hypertension.