This is a large-scale epidemiological prospective cohort study. The research protocol was approved by the China Medical University Research Ethics Committee, and written informed consent was formally obtained from all the participants or their guardians. Therefore, this study aimed to investigate the association between stage 1 hypertension defined by the 2017 ACC/AHA guideline and the risk of stroke and its subtypes among adults aged ≥60 years using the data from rural areas of China. These studies did not specifically analyze the relationship between stage 1 hypertension and stroke and its subtypes, especially in rural elderly Chinese. The findings of previous studies in different countries concerning CVD risk associated with stage 1 hypertension in the new guideline are controversial. In contrast, stronger associations with subsequent CVD events were observed in those with baseline stage 1 hypertension among Korean young adults. Similarly, another study demonstrated that the newly defined stage 1 hypertension was not associated with increased risk of CVD mortality among Chinese in Singapore aged 46–85 years. A data from the Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA)/Cooperative Health Research in the Region of Augsburg (KORA) cohort study involving 11,603 subjects showed that stage 1 hypertension did not increase the risk of cardiovascular disease (CVD) mortality compared with normal BP. Many countries in Europe or Asia have carefully considered whether the new guideline is suitable for localization across the difference of geographical regions and ethnicities.
If China follows the guideline, the prevalence of hypertension will increase from 23.2% to 46.4% and would be higher in the elderly. The prevalence of Korean adults with hypertension increased from 28.0% (Seventh Joint National Committee, JNC-7) to 47.9% (2017ACC/AHA guideline). Meanwhile, the prevalence of hypertension added under this new definition was concerned by other Asian countries. In 2017, the American College of Cardiology and American Heart Association (ACC/AHA) released a new guideline, defining systolic/diastolic blood pressure (SBP/DBP) of 130 to 139/80 to 89 mmHg as stage 1 hypertension. For this reason, China should pay more attention to blood pressure (BP) in the elderly. The prevalence of hypertension positively increased with age. Currently, with the development of economy, the improvement of medical conditions, and the rise in life expectancy, the number of the elderly population in China has increased substantially. Hypertension is a major risk factor for stroke, and the prevalence of hypertension will continue to increase, especially in rural areas.
In China, recent studies have found that hemorrhagic stroke mortality has decreased however, morbidity and mortality of hemorrhagic stroke are nearly twice as the global average, and the burden of ischemic stroke is still increasing. Stroke is the leading cause of death in China. Among adults aged ≥60 years in rural China, stage 1 hypertension defined by 2017 American College of Cardiology and American Heart Association hypertension guideline was independently associated with the increased risk of all stroke and ischemic stroke, excluding hemorrhagic stroke. In this study, the population attributable risk values of stage 1 hypertension were 10.22% (2.64%–18.56%) for all stroke and 14.34% (4.23%–25.41%) for ischemic stroke. With the blood pressure <120/<80 mmHg as a reference, stage 1 hypertension showed the adjusted hazard ratios (95% confidence intervals) of 1.45 (1.11–1.90) for all stroke, 1.65 (1.17–2.33) for ischemic stroke, and 1.17 (0.74–1.85) for hemorrhagic stroke, respectively. During a median follow-up of 12.5 years, we observed 1,159 first-ever incident stroke (774 ischemic, 360 hemorrhagic, and 25 uncategorized). Adjusted Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals with the normal blood pressure as a reference, and calculated population attributable risk was based on prevalence and hazard ratios. Follow-up for the new cases of stroke was conducted from the end of the baseline survey to the end of the third follow-up survey (January 1, 2007–December 31, 2017). This population-based cohort study consisted of 7,503 adults aged ≥60 years with complete data and no cardiovascular disease at baseline from rural areas of Fuxin County, Liaoning province, China. However, the association of stage 1 hypertension with stroke and its subtypes among the older population in rural China remains unclear. The 2017 American College of Cardiology and American Heart Association hypertension guideline updated stage 1 hypertension definition as systolic blood pressure range from 130 to 139 mmHg or diastolic blood pressure from 80 to 89 mmHg.