Epidemiology of hypertension in the elderly.

In Western populations, mean systolic and diastolic blood pressures rise with advancing age up to the sixth decade of life, whereupon systolic blood pressure continues to increase and diastolic pressure starts to decline. The ensuing widening of pulse pressure is mainly ascribed to stiffening of the arterial vasculature. When hypertension is defined as systolic blood pressure of at least 140 mm Hg and/or diastolic pressure of at least 90 mm Hg, its prevalence amounts to 60%-70% of the population above 60 years of age. About 60% of these hypertensives have isolated systolic hypertension--that is, elevated systolic pressure and normal diastolic pressure. It should be realized, however, that approximately 25% of those labeled hypertensive on the basis of conventional blood pressure measurements have normal blood pressure on ambulatory blood pressure monitoring, or so-called white-coat, isolated clinic, or nonsustained hypertension. There is little doubt that elevated blood pressure leads to a number of cardiovascular complications. Whereas diastolic blood pressure has been emphasized for many years, the paradigm has shifted toward systolic blood pressure. In addition, pulse pressure has been shown to be an important predictor of cardiovascular events and death, above and beyond the predictive power of mean blood pressure.