Dry-weight reduction in hypertensive hemodialysis patients (DRIP): a randomized, controlled trial

Abstract

Volume excess is thought to be important in the pathogenesis of hypertension among hemodialysis patients. To determine whether additional volume reduction will result in improvement in blood pressure (BP) among hypertensive patients on hemodialysis and to evaluate the time course of this response, we randomly assigned long-term hypertensive hemodialysis patients to ultrafiltration or control groups. The additional ultrafiltration group (n=100) had the dry weight probed without increasing time or duration of dialysis, whereas the control group (n=50) only had physician visits. The primary outcome was change in systolic interdialytic ambulatory BP. Postdialysis weight was reduced by 0.9 kg at 4 weeks and resulted in -6.9 mm Hg (95% CI: -12.4 to -1.3 mm Hg; P=0.016) change in systolic BP and -3.1 mm Hg (95% CI: -6.2 to -0.02 mm Hg; P=0.048) change in diastolic BP. At 8 weeks, dry weight was reduced 1 kg, systolic BP changed -6.6 mm Hg (95% CI: -12.2 to -1.0 mm Hg; P=0.021), and diastolic BP changed -3.3 mm Hg (95% CI: -6.4 to -0.2 mm Hg; P=0.037) from baseline. The Mantel-Hanzel combined odds ratio for systolic BP reduction of > or =10 mm Hg was 2.24 (95% CI: 1.32 to 3.81; P=0.003). There was no deterioration seen in any domain of the kidney disease quality of life health survey despite an increase in intradialytic signs and symptoms of hypotension. The reduction of dry weight is a simple, efficacious, and well-tolerated maneuver to improve BP control in hypertensive hemodialysis patients. Long-term control of BP will depend on continued assessment and maintenance of dry weight.

Trial registration: ClinicalTrials.gov NCT00067665.

Figure 1

Enrollment and Trial flow.

Figure 2

The effect of dry-weight reduction on interdialytic ambulatory systolic (Panel A) and diastolic blood pressure (Panel B) in hypertensive hemodialysis patients. The mean systolic and diastolic blood pressures are shown for the baseline control and ultrafiltration groups. The mean changes in blood pressure are shown for weeks 4 and 8 following randomization (solid arrows), and the mean differences in blood pressures (dotted arrows) between the two groups at each 4 week interval. The numbers next to the dotted lines connecting the data points are the mean changes in blood pressure between groups at 4 and 8 weeks following randomization. The 95% confidence intervals are given in parentheses. Asterisks (p<0.05), daggers (p<0.01) and double daggers (p<0.001) indicate significant differences between groups or within groups. The ultrafiltration-attributable change in systolic BP was -6.9 mm Hg (95% CI -12.4, -1.3 mm Hg, p=0.016) at 4 weeks and -6.6 mm Hg (95% CI -12.2, -1.0 mm Hg, p=0.021) at 8 weeks. The ultrafiltration-attributable change in diastolic BP was -3.1 mm Hg (95% CI -6.2, -0.02 mm Hg, p=0.048) at 4 weeks and -3.3 mm Hg (95% CI -6.4, -0.2 mm Hg, p=0.037) at 8 weeks.

Figure 3

Relationship of change in systolic ambulatory blood pressure with ultrafiltration compared to the change in post-dialysis weight. Changes depict the reduction in systolic blood pressure at 4 weeks (circles) and 8 weeks (triangles) from baseline plotted against changes in post-dialysis weight at 4 weeks and at 8 weeks. Regression lines reflect the linear relationships at 4 weeks (blue line) and at 8 weeks (green line)

Figure 4

Reduction in systolic ambulatory blood pressure with ultrafiltration compared to the control group. Changes depict the reduction in systolic blood pressure at 4 weeks (grey circles) and 8 weeks (brown circles) and their 95% confidence intervals. Only the interaction between ultrafiltration and race was significant (p=0.01). The size of the circles is proportional to the number of patients.