Assessment of Prevalence, Awareness, and Characteristics of Isolated Systolic Hypertension Among Younger and Middle-Aged Adults in China.

Importance: Isolated systolic hypertension (ISH) is increasing in prevalence among young and middle-aged adults. However, most studies of ISH are limited to older individuals, and a substantial knowledge gap exists regarding younger adults with ISH. Objective: To assess the prevalence, awareness, and characteristics of ISH among younger and middle-aged adults in China. Design, Setting, and Participants: This cross-sectional study was performed as part of the China Patient-Centered Evaluative Assessment of Cardiac Events Million Persons Project, which enrolled 3.1 million community residents aged 35 to 75 years from all of the 31 provinces in China between December 15, 2014, and May 15, 2019. The present analysis included only participants younger than 50 years. Data were analyzed from May to November 2019. Main Outcomes and Measures: Prevalence and awareness of ISH (defined as systolic blood pressure of 140 mm Hg or higher and diastolic blood pressure of less than 90 mm Hg) and individual characteristics of participants with ISH. Results: Among 898 929 participants aged 35 to 49 years, the mean (SD) age was 43.8 (3.9) years; 548 657 participants (61.0%) were women, and 235 138 participants (26.2%) had hypertension. Of those with hypertension, 62 819 participants (26.7%; 95% CI, 26.5%-26.9%) had ISH (mean [SD] age, 45.0 [3.5] years; 41 417 women [65.9%]), and 54 463 of those with ISH (86.7%; 95% CI, 86.4%-87.0%) had not received treatment. The prevalence of ISH was higher among individuals who were older, were female, were farmers, resided in the eastern region of China, and had an educational level of primary school or lower. Women and older individuals were more likely to have ISH than to be normotensive or to have other hypertension subtypes. Participants who were obese, currently used alcohol, had diabetes, and experienced previous cardiovascular events were more likely to have other types of hypertension and less likely to have normotension than to have ISH. Among the 54 463 participants with ISH who had not received treatment, only 3682 individuals (6.8%; 95% CI, 6.6%-7.0%) were aware of having hypertension, and awareness rates remained low even among those with systolic blood pressure of 160 mm Hg or higher (7135 individuals [13.1%; 95% CI, 12.4%-13.9%]). Conclusions and Relevance: In this study, ISH was identified in 1 of 4 young and middle-aged adults with hypertension in China, most of whom remained unaware of having hypertension. These results highlight the increasing need for better guidance regarding the management of ISH in this population.