What is the Clinical Relevance of Isolated Systolic Hypertension?

Abstract

During normal aging, systolic blood pressure (SBP) rises and a large proportion of elderly people develop isolated systolic hypertension (ISH). ISH was previously considered to be a normal mechanism that was able to preserve brain, coronary and kidney blood flow despite the development of atherosclerosis. The European Working Party on Hypertension in the Elderly (EWPHE) trial (Amery et aL 1985;Staessen et aL 1989) and the Systolic Hypertension Elderly Program (SHEP Cooperative Research Group 1991) have modified the ideas concerning the epidemiology of and the therapeutic possibilities for treating ISH in the elderly. PrevalenceIn most developed countries advancing age is associated with a progressive and continuous rise in SBP to levels of 150mm Hg by the age of 70 to 80 years. Diastolic blood pressure (DBP) generally does not increase after middle age (50 to 60 years) and in fact may decrease gradually after the age of 60 years. The age-related increase in SBP is accompanied by an increasing prevalence of ISH, which is generally defined as SBP ~ 160mm Hg with a DBP < 95mm Hg in some studies, and < 90mm Hg in others (Dustan 1989). The epidemiology of hypertension in the elderly is reviewed later in this issue (Morgenstern & Byyny 1992).After middle age the prevalence of ISH rises progressively in both sexes becoming the most common form of hypertension in the population over the age of 60 years (Saltzberg et aL 1988). In North America the prevalence of ISH was determined in a representative sample of the entire population of noninstitutionalised adults by the National Health Examination Survey using the criteria ofSBP > 160mm Hg and DBP < 95mm Hg.Blood pressure was taken as the average of 3 sitting readings measured at 25-minute intervals during a single visit. The prevalence progressively increased with age regardless of sex or race. In most age groups, a higher incidence was found for Blacks compared with Whites, and women compared with men; for example the incidence in both women and men between the ages of 70 to 79 years was 14%, and for those 80 years and over was 21 % and 17%, respectively (SHEP Cooperative Research Group 1991).Similar findings have been observed in Europe. In the southwest of France, the prevalence of ISH increased from 12.1 % in people between the ages of 65 to 69 years to 19.1 % in those between the ages of 75 to 90 years (Emeriau et aL 1988). In a Belgian study, SBP and DBP were measured 5 times consecutively on each of 2 separate home visits at intervals ~ 1 day; the prevalence of ISH (DBP < 95mm Hg) decreased from 14 to 9.5% between the first and second visits (Staessen et aL 1990).Two points must be discussed. First, should the cut-off point for DBP be < 95 or < 90mm Hg? If the cut-off point is < 90mm Hg the prevalence is 8%, which is considerably lower than that found

Epidemiology of Hypertension in the Elderly

“…These trials, combined with results from smaller trials studying individual drugs, show that drug treatment in the elderly can be effective and relatively safe, if done with care. The clinical relevance of isolated systolic hypertension is discussed elsewhere in this issue (Emeriau 1992).…”