β-Blocker Treatment Does Not Alter Peak Oxygen Uptake (VO2 Peak) in Patients Undergoing Hemodialysis

Background: Severely impaired cardiovascular functional capacity (CVC) is a predominant manifestation in patients with heart failure in advanced CKD, where β-blockers (BBs) are a key therapy for this condition and are often continued after hemodialysis (HD) initiation. However, there remain safety concerns on whether BBs could worsen CVC in patients on HD, given that blunting of oxygen uptake at peak exercise (VO2Peak – gold-standard index for CVC) has been observed in the general heart failure population. Herein, we examined the influence of BB treatment on VO2Peak in patients on HD. Methods: We conducted a cross-sectional study of 38 patients on HD who underwent cardiopulmonary exercise testing (CPET) and echocardiography in the ECON and SPARK trials. Patients were stratified into BB (n=20) and non-BB (n=18) groups. Groups were compared using independent t-tests or Chi-squared tests. CPET-derived variables were adjusted by age and sex and reported as adjusted least-square means ± standard error. Multiple regression models were adjusted for the same variables. Results: The BB and non-BB groups were well-matched with respect to sex, race, BMI, and frequency of hypertension and diabetes diagnoses (all P>0.05). Additionally, dialysis vintage, hemoglobin levels, resting blood pressure and heart rate (HR) were similar between groups (all P>0.05). However, the BB group was significantly younger (47±10 y) than the non-BB group (58±12 y; P=0.002). No differences were observed in left ventricular ejection fraction (BB: 63.3±14.5, non-BB: 62.3±9.6%; P=0.86). Both groups achieved RER>1.0, confirming maximal effort on CPET. Adjusted VO2Peak was similar between the BB (12.9±0.77 mL/min/kg) and non-BB groups (12.9±0.73 mL/min/kg; P=0.99). Similarly, the adjusted peak HR was not significantly reduced in the BB group (104±4 bpm) compared to the non-BB group (112±4 bpm; P=0.18), and peak workload was comparable between the two groups (P=0.80). Multiple regression demonstrated that BB use showed no association with VO2Peak (P=0.99) or peak HR (P=0.18). Conclusion: The study findings demonstrate that CVC (as assessed by VO2Peak) is not influenced by BB treatment in patients on HD. The findings shed light on the BB safety profile in patients on HD and provide strong rationale for further validation studies, and to evaluate the role of cardioselective versus non-cardioselective BBs. Funding: Other NIH Support - Indiana University Health Vales Fund for Research Award and the Indiana Clinical and Translational Sciences Institute funded, in part by Grant # UL1TR001108 from the National Institutes of Health, National Center for Advancing Translational Sciences, Clinical and Translational Sciences Award; Paul Teschan Research Fund (PTRF), Dialysis Clinic Inc (DCI), Private Foundation Support