Systolic hypertension: the nephrologist's point of view

The elevation of systolic blood pressure associated with aging has been considered for years a physiologic phenomenon. This idea was based on the repeated observation that, also after middle age, a large majority of individuals in industrialized countries experience a continuous and progressive increase over time in systolic blood pressure, not in diastolic blood pressure. However, some individuals in industrialized countries and most individuals in nonindustrialized countries do not acquire an increased systolic blood pressure over time proving that the age-associated rise in systolic blood pressure is not an inevitable phenomenon. The change in systolic blood pressure over time strongly reflects lifestyles. Diet-dependent factors such as body weight, alcohol intake, and balance between dietary salt and potassium, are important in favoring the age-associated increase in systolic blood pressure, independently of several confounders. Epidemiologic studies suggest that elevation of systolic blood pressure is a risk factor for cardiovascular diseases: it relates to high incidence of lethal and nonlethal cardiovascular events also in the presence of diastolic blood pressure in the nonhypertensive range. Controlled clinical trials show that the treatment of isolated systolic hypertension reduces the number of cardiovascular events. In addition to cardiovascular disease, systolic blood pressure relates also to microalbuminuria, an index of early glomerular damage, to long-term incidence of end-stage renal disease, and, in hemodialyzed patients, to premature death. Thus, high systolic blood pressure appears an unhealthy condition also for patients with or at risk for kidney diseases.