Age-related blood pressure patterns and blood pressure variability among hemodialysis patients

Background and objectives: Despite the high prevalence of cardiovascular disease among hemodialysis patients, the relationship between age and blood pressure (BP) is not well understood. It was postulated that the relationship of BP to age differs among hemodialysis patients versus the general population and that there is significant variability in dialysis unit BP measurements. Design, setting, participants, & measurements: To explore this hypothesis, the patterns of systolic, diastolic, mean arterial, and pulse pressures in the general population using data from National Health and Nutrition Examination Survey participants (n = 9242) were compared with those in a cohort of hemodialysis patients (n = 9849). Results: In contrast to the increase in systolic BP with age in the general population, systolic BP was elevated in young hemodialysis patients and declined slightly among the elderly. The inverted "U"-shape relationship between age and diastolic BP in the general population was absent in hemodialysis patients. Diastolic BP was elevated among hemodialysis patients <50 yr of age and declined with advancing age. Mean arterial and pulse pressures were elevated among young hemodialysis patients and exhibited less age dependency than in the general population. Variability in BP within patients was similar to that between patients. Conclusions: The relationship of BP to age differed from that in the general population. The variability in dialysis unit BP measurements may limit their use in managing hypertension and predicting outcomes. Nevertheless, dialysis unit BP measurements are necessary to minimize acute complications during the dialysis procedure.