Hypertension awareness, blood pressure severity, and all-cause mortality: independent analyses of population-based cohorts in China and the United States

Abstract

To examine whether self-reported hypertension awareness was associated with all-cause mortality after accounting for baseline blood pressure (BP) severity and control, and whether mortality differed between aware and unaware participants within the same BP severity categories. We included adults aged 45 years or older from the China Health and Retirement Longitudinal Study (CHARLS; baseline 2011–2012) and the US National Health and Nutrition Examination Survey (NHANES; 1999–2018). Hypertension awareness was defined as a self-reported previous diagnosis of hypertension by a physician or other health professional. Participants were assigned to five mutually exclusive categories based on this awareness status and baseline measured BP: normotension, aware controlled hypertension, aware uncontrolled hypertension, unaware grade 1 hypertension, and unaware grade 2–3 hypertension. The two cohorts were analyzed independently using a broadly common analytical framework, with cohort-specific Cox proportional hazards models incorporating the appropriate weighting and adjustment for demographic, lifestyle, and clinical covariates. We additionally compared aware and unaware hypertension within the same BP severity categories and modeled continuous systolic BP (SBP) in relation to mortality. The analytic samples comprised 12,868 participants in CHARLS, of whom 12,640 contributed mortality follow-up, and 26,351 participants in NHANES. Compared with normotension, aware, uncontrolled hypertension was associated with higher mortality in both CHARLS (HR, 1.53; 95% CI, 1.26–1.85) and NHANES (HR, 1.39; 95% CI, 1.28–1.52). Unaware grade 2–3 hypertension showed similar associations (CHARLS: HR, 1.58; 95% CI, 1.25–1.99; NHANES: HR, 1.50; 95% CI, 1.29–1.76). Within the same broad BP severity categories, awareness status was not consistently associated with mortality across the two cohorts. Mortality increased with continuous SBP in both cohorts; evidence of an SBP-by-awareness interaction was observed in NHANES but not in CHARLS. The main phenotype associations did not differ significantly between the cohorts. In these two population-based cohorts, baseline BP severity and control categories showed more consistent associations with all-cause mortality than self-reported hypertension awareness status. Within the same broad BP severity categories, awareness status was not consistently associated with mortality across the two cohorts. These observational findings describe associations among baseline-defined phenotypes and should not be interpreted as evidence that hypertension awareness itself is unimportant. Hypertension detection remains important and should be followed by continued clinical follow-up and sustained BP control.