The significance of low DBP in US adults with isolated systolic hypertension

Abstract

To determine the features of isolated systolic hypertension (ISH), the most common hypertensive subtype in persons at least age 50, associated with greater cardiovascular disease (CVD) risk when accompanied by low diastolic blood pressure (DBP). Data were obtained from adult hypertensives at least age 18 in the National Health Nutrition Examination Survey (NHANES) 1999-2006 (n = 19 808, projected to 199.3 million). ISH were categorized by low DBP (< 70 mmHg) vs. higher DBP (≥ 70-89 mmHg), treatment status, age, sex, ethnicity, cardiometabolic risk factors, and comorbidities. A 58.6% of all untreated US hypertensives had ISH (mean blood pressure 154.3/73.8 mmHg). Untreated and treated persons with ISH and DBP less than 70 mmHg represented 30 and 35%, respectively, of the ISH population and had almost twice the prevalence of diabetes and CVD, but a lower prevalence of the metabolic syndrome (P < 0.05 to P < 0.01). There was a three-fold greater prevalence of CVD from the highest to the lowest DBP strata in untreated ISH (P < 0.01). Logistic regression showed that age, female sex, and diabetes, but not treatment status, were independently associated with lower DBP (all P < 0.01). Of those persons with ISH and DBP less than 70 mmHg, 45% remain untreated. Older persons with untreated ISH and DBP less than 70 mmHg, comprising almost one-third of the untreated ISH population, had greater prevalence of diabetes and CVD than persons with ISH in association with DBP 70-89 mmHg. Intensified efforts to identify and adequately treat these individuals are needed to reduce their associated CVD risk.