MO466: Impact of Renal Insufficiency on Choice of Rhythm or Rate Control in Atrial Fibrillation and Subsequent Effects on Cardiovascular and Mortality Outcomes
Authors: Baumbach Zille , Illum Emilie , Linnea Freese Ballegaard Ellen , Haagensen Kofod Dea , Nelveg-Kristensen Karl-Emil , Schou Morten , Gislason Gunnar , Torp Christian , Hornum Mads , Carlson Nicholas 
Published: May 2022

Abstract

BACKGROUND AND AIMS
Atrial fibrillation remains the most common sustained arrhythmia in the general population, with prevalence inversely correlated with renal function. Management of atrial fibrillation relies on either rhythm control or rate control, however, the choice of treatment in patients with impaired renal function remains contentious. Accordingly, we examined clinical practice and subsequent treatment outcomes.

METHOD
Based on nationwide healthcare registers, all patients with atrial fibrillation were identified in Denmark between 2000 and 2021. Patients aged &lt; 18 years, and with previous prescriptions on amiodarone, digoxin, beta-blockers, calcium antagonists, or anti-coagulative medicine, or without a pre-existent record of creatinine level were excluded. Patients were stratified into two groups receiving either rhythm or rate control with the expulsion of patients with no treatment. Baseline renal function was calculated using the CKD-EPI equation based on recent plasma creatinine. The probability of rhythm control versus rate control stratified on estimated glomerular filtration rate (eGFR) (&gt;90mL/min/1.73m2, 60–90 mL/min/1.73m2, 30–60 mL/min/1.73m2, &lt;30 mL/min/1.73m2) was estimated using odds ratios based on multiple logistic regression with a subsequent appraisal of the risk of cardiovascular outcomes and death based on the Aalen–Johansen and Kaplan–Meier estimators, respectively and multiple Cox regression.

RESULTS
A total of 37 920 patients were included. Rate control (n = 34 315) was associated with even gender distribution (female gender 50.1%), mean age 74.5 (SD ± 11.8) years and median eGFR 75.9 (IQR 59.9–87.8 mL/min/1.73m2). Rhythm control (n = 3605) was associated with predominantly male gender (66.4%), a mean age of 68.5 (SD ± 12.1) and median eGFR 81.2 (IQR 66.4–91.6 mL/min/1.73m2). eGFR-stratified odds ratios for rhythm control versus rate control were 0.91 (95% CI 0.84–1.0) for eGFR 60–90 mL/min/1.73m2, 0.85 (0.75–0.96) for eGFR 30–60 mL/min/1.73m2 and 0.77 (0.61–0.98) for eGFR &lt; 30 mL/min/1.73m2 compared to patients with eGFR &gt; 90 mL/min/1.73m2 .
With rate control as reference, adjusted hazard ratios for subsequent cardiovascular outcomes were 1.51 (95% CI 1.40–1.62) for eGFR &gt; 90 mL/min/1.73m2, 1.53 (1.45–1.62) for eGFR 60–90 mL/min/1.73m2, 1.86 (1.68–2.05) for eGFR 30–60 mL/min/1.73m2 and 1.88 (1.47–2.41) for eGFR &lt; 30 mL/min/1.73 m2. Cumulative risks of cardiovascular outcomes are shown in Figure 1.
Adjusted hazard ratios for subsequent all-cause mortality, with rate control as reference, were 1.19 (95% CI 0.95–1.5) for eGFR &gt; 90 mL/min/1.73m2, 1.11 (0.96–1.29) for eGFR 60–90 mL/min/1.73m2, 1.25 (1.05–1.55) for eGFR 30–60 mL/min/1.73m2 and 1.66 (1.08–2.54) for eGFR &lt; 30 mL/min/1.73 m2. Survival curves are shown in Figure 2.

CONCLUSION
Rhythm control was less likely employed and was associated with a progressively increased risk of cardiovascular and mortality outcomes in patients with renal insufficiency as compared to rate control; thus, supporting contemporary clinical practice where the choice of rate control appears to prevail.