Isolated systolic hypertension and central blood pressure: Implications from the national nutrition and health survey in Taiwan

We aimed to investigate the association between isolated systolic hypertension (ISH) and central blood pressure (BP) in a nationally representative population, with a focus on the young and middle-aged adults (<50 years old). A total of 2029 adults without taking antihypertensive medications, aged ≥ 19 years old, participated in the 2013–2016 National Nutrition and Health Survey in Taiwan. Central and brachial BP were simultaneously measured using a cuff-based stand-alone central blood pressure monitor purporting to measure invasive central BP (type II device). Central hypertension was defined by central systolic (SBP)/diastolic BP (DBP) ≥130 or 90 mm Hg, and ISH was defined by brachial SBP ≥ 140 and DBP < 90 mm Hg. Overall, the prevalence rates of ISH, isolated diastolic hypertension (IDH, brachial SBP < 140 and DBP ≥ 90 mmHg), and systolic/diastolic hypertension (SDH, brachial SBP ≥ 140 and DBP ≥ 90 mmHg) were 6.51%, 1.92%, and 4.34%, respectively. ISH subjects had significantly higher central pulse pressure (PP) (62.8 ± 9.7 mm Hg for age < 50 years and 72.4 ± 13.5 mmHg for age ≥ 50 years) than those subjects with either IDH (44.7 ± 10.7 and 44.9 ± 10.6 mmHg) or SDH (55.2 ± 14.0 and 62.6 ± 17.1 mmHg). All ISH adults had central hypertension, and a higher prevalence of central obesity than the normotensives (80.95% vs. 26.15%, for age < 50 years; and 63.96% vs. 43.37% for age ≥ 50 years). All untreated subjects with ISH, whether younger or older, had central hypertension and had significantly higher central PP than those with IDH or SDH. Central obesity was one of the major characteristics of ISH, especially in the young- and middle-aged adults.