Nondialyzable versus Dialyzable Beta-Blockers in Hemodialysis

Background: How beta-blocker dialyzability affects cardiovascular outcomes in patients receiving hemodialysis remains unclear. Previous observational studies show conflicting results, and conducting clinical trials in this population has proven challenging. This uncertainty has contributed to substantial variation in beta-blocker prescribing patterns across regions and clinicians. Methods: Using data from the United States (US) Renal Data System, we identified patients receiving beta-blockers on the day of starting hemodialysis and classified them into nondialyzable and dialyzable exposure groups. Geographical variations in nondialyzable and dialyzable beta-blocker prescription rates across neighboring regions in each state were leveraged as an instrumental variable. The treatment effect of nondialyzable vs dialyzable beta-blockers on major adverse cardiovascular events (MACE) at 6 months, 1 year, and 3 years was evaluated using instrumental variable g-estimation methods for survival outcomes. MACE comprised myocardial infarction, stroke, and all-cause mortality. Results: The cohort of 40,313 participants from 41 US states experienced 25,720 MACE over the 3-year follow-up period (median years [interquartile range]: 1.4 [0.4 to 3.0]), with more than 42% occurring during the first 6 months after hemodialysis initiation. The instrumental variable met all statistical assumptions. Nondialyzable beta-blockers were associated with significantly lower risk of MACE at all three follow-up timepoints compared to dialyzable beta-blockers (hazard ratios [95% confidence intervals]: 0.82 [0.74 to 0.90], 0.85 [0.79 to 0.92] and 0.90 [0.85 to 0.96]). Similar patterns were observed for each separate component of MACE. Conclusions: The use of nondialyzable beta-blockers compared to dialyzable beta-blockers was associated with lower risk of MACE during all time points, including the early, high-risk period in the 6 months following hemodialysis initiation.