Hypertension and Risk for Cardiovascular Mortality

Study Questions:

What is the prevalence, diagnosis, treatment, and control of hypertension and the cardiovascular disease (CVD) mortality attributable to hypertension in China?

Methods:

This prospective cohort study (China Kadoorie Biobank Study) recruited 500,223 adults, aged 35-74 years, from the general population in China. Blood pressure (BP) measurements were recorded as part of the baseline survey from June 25, 2004 to August 5, 2009, and 7,028 deaths due to CVD were recorded before January 1, 2014 (mean duration of follow-up, 7.2 years). Data were analyzed from June 9, 2014 to July 17, 2015. Prevalence and diagnosis of hypertension (systolic BP ≥140 mm Hg, diastolic BP ≥90 mm Hg, or receiving treatment for hypertension) and treatment and control rates overall and in various population subgroups were analyzed. Cox regression analysis yielded age- and sex-specific rate ratios for deaths due to CVD comparing participants with and without uncontrolled hypertension, which were used to estimate the number of CVD deaths attributable to hypertension.

Results:

The cohort included 205,167 men (41.0%) and 295,056 women (59.0%) with a mean (standard deviation) age of 52 (10) years for both sexes. Overall, 32.5% of participants had hypertension; the prevalence increased with age (from 12.6% at 35-39 years of age to 58.4% at 70-74 years of age) and varied substantially by region (range, 22.7%-40.7%). Of those with hypertension, 30.5% had received a diagnosis from a physician; of those with a diagnosis of hypertension, 46.4% were being treated; and of those treated, 29.6% had their hypertension controlled (i.e., systolic BP <140 mm Hg; diastolic BP <90 mm Hg), resulting in an overall control rate of 4.2%. Even among patients with hypertension and prior CVD, only 13.0% had their hypertension controlled. Uncontrolled hypertension was associated with relative risks for CVD mortality of 4.1 (95% confidence interval [CI], 3.7-4.6), 2.6 (95% CI, 2.4-2.9), and 1.9 (95% CI, 1.8-2.0) at ages 35-59, 60-69, and 70-79 years, respectively, and accounted for about one-third of deaths due to CVD (approximately 750,000) at 35-79 years of age in 2010.

Conclusions:

The authors concluded that levels of diagnosis, treatment, and control of hypertension among Chinese adults were much lower than in Western populations, and were associated with significant excess mortality.

Perspective:

This study reports that about one-third of the adult Chinese population had hypertension with <5% of participants with hypertension with properly controlled BP. Undertreatment was observed in all regions and subgroups assessed, including those with prior CVD. Furthermore, uncontrolled hypertension was estimated to cause 750,000 CVD deaths annually in China. Public health initiatives are indicated in China that focus on the major determinants of BP at a population level, with ongoing research to identify the most effective population-level approaches for BP control in China. Such population-based approaches will have significant impact on reducing CVD mortality in China.

Clinical Topics: Diabetes and Cardiometabolic Disease, Prevention, Hypertension

Keywords: Blood Pressure, Cardiovascular Diseases, Hypertension, Metabolic Syndrome X, Mortality, Prevalence, Primary Prevention, Risk, Quality of Health Care


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