Uncontrolled Hypertension Linked to Beta Blockers in HD Patients
SEATTLE—Beta-blocker therapy may be associated with an increase in uncontrolled hypertension, paradoxical hypertension and muscular cramps in hemodialysis (HD) patients, according to a new study presented at the 33rd Annual Dialysis Conference.
The study also showed that HD patients on beta-blocker therapy are less tolerant of ultrafiltration (UF) and consequently may have larger extra-cellular fluid volume.
“Beta blockers may not be as effective as we once thought and it may be limiting our ability to get [HD patients] to their dry weight,” said investigator Raj Munshi, MD, an advanced dialysis fellow at the University of Washington in Seattle.
Controlling hypertension in HD patients is critical to reduce cardiovascular complications, Dr. Munshi said. The best results are demonstrated when ultrafiltration (UF) is successful in achieving dry weight and normalizing blood pressure (BP).
He and his colleagues Shu-Hong Bi, MD, and Suhail Ahmad, MD, studied 50 HD patients whom they divided into two groups based on fluid volume status: low volume (LV) and high volume (HV). All patients had been on thrice-week dialysis for at least six months. Body composition by multi-frequency bioelectrical impedance analysis measurements was determined by extracellular water/total body water (ECW/TBW). Fluid volume status was calculated by the mean value of ECW/TBW.
Patients with the ECW/BW higher and lower than the mean value were defined as the HV group and LV group, respectively. The researchers determined body composition by BIA before and after dialysis on the same day. They defined hypertension according to World Health Organization criteria. Antihypertensive mediations were recorded in detail to calculate the defined daily dose.
Dr. Munshi's group found that 18 of 50 patients were receiving beta-blocker therapy (BB group) and 32 were not (non BB group). The pre-dialysis BP in the BB group was similar to that of the non-BB group, but post-dialysis systolic BP was significantly higher in the BB group (143 vs. 126 mm Hg in non-BB group). Additionally, the ECW fraction of TBW was higher in BB group (25% vs. 24% in non-BB group). Significantly more patients in the BB group than the non-BB group complained of muscle cramps during dialysis than non-BB group (44.4% vs. 12.5%).
“The majority of our patients are hypertensive and they have other cardiovascular co-morbidities, so beta-blockers tend to be a natural choice,” said Dr. Munshi, who added that according to the U.S. Renal Data System, up to two-thirds of HD patients are on beta-blockers. “This study should give us a moment of pause.”
The study showed that ACE inhibitor use was associated with a similar trend, but the association was not statistically significant.
Dr. Munshi noted that the study was limited by its observational design, small sample size, and lack of a healthy control group.