Hypertension is Not Adequately Controlled in Hemodialysis Patients

Abstract

To examine the adequacy of hypertension control, we monitored the blood pressure (BP) of 53 hemodialysis patients who received treatment for hypertension. BP measurement using an ambulatory BP monitor began 1 hour before dialysis and continued every 30 to 60 minutes for 48 hours until the next dialysis. Diet, medications including antihypertensive drugs, and hemodialysis prescription were not changed during this study. Each patient had a mean of 68 BP measurements during the monitoring period. Mean (±SD) systolic and diastolic BP levels of all patients over 48 hours were 158.6 ± 22.7 mm Hg and 88.7 ± 16.6 mm Hg, respectively, without diurnal variations. In these, BP loads (the percentage of systolic BP exceeding 150 mm Hg and diastolic BP exceeding 90 mm Hg) were 58.4% and 39.4%, respectively, suggesting that hypertension was inadequately controlled for more than half of the study period. Eight patients (15%) maintained BP within normal ranges at all times. All patients lost weight (2.9 ± 0.9 kg) at the end of dialysis by ultrafiltration. However, only 27 patients (51%) had a greater than 5% decrease in mean arterial BP postdialysis, which returned to predialysis levels within 12 to 24 hours. Reduction of BP postdialysis was significantly more common among black patients (72%) than white patients (30%) ( P < 0.01). However, there was no difference in age, cause of kidney disease, amount of ultrafiltration, and BP loads between those whose BP decreased and those whose did not. BP monitoring was repeated in eight patients, 2 to 3 months after adjustment of their antihypertensive regimens. In the repeat study, systolic BP loads were 18.4%, compared with 77.1 % in the previous study. ( P < 0.001). In summary, (1) hypertension is not adequately controlled in the majority of hemodialysis patients despite antihypertensive treatment; (2) only half of hypertension patients have a decrease in BP at the end of dialysis, which returns to predialysis levels between 12 and 24 hours; (3) reduction of BP in response to ultrafiltration is significantly more common in blacks than whites, suggesting a different mechanism is operational in maintaining hypertension among races; (4) circadian rhythm in BP is not preserved; and (5) continuous ambulatory BP monitoring helps improve hypertension control. We conclude that a considerable number of hemodialysis patients who are treated for chronic hypertension do not have adequate control of hypertension. This finding may explain, at least partially, why cardiac and cerebrovascular disease remain the major causes of death in dialysis patients.