Objectives: 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).
Design: 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).
Method: ISH were categorized by low DBP (<70 mmHg)
vs. higher DBP (≥70–89 mmHg), treatment status, age,
sex, ethnicity, cardiometabolic risk factors, and
comorbidities.
Results: 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.
Conclusion: 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.
