Association Between Sodium- and Potassium-Related Urinary Markers and the Prevalence of Atrial Fibrillation.

Background: The primary prevention of atrial fibrillation (AF), which increases mortality through complications including stroke and heart failure, is important. Excessive salt intake and low potassium intake are risk factors for cardiovascular disease; however, their association with AF remains inconclusive. This study investigated the association between sodium- and potassium-related urinary markers and AF prevalence.

Methods And Results: Data from the Tohoku Medical Megabank Project Community-based Cohort Study were used in this cross-sectional study. The urinary sodium-to-potassium (Na/K) ratio and estimated 24-h sodium and potassium excretion were calculated using spot urine samples and categorized into quartiles (Q1-Q4). The prevalence of AF was the primary outcome. Of the 26,506 participants (mean age 64.8 years; 33.2% males) included in this study, 630 (2.4%) had AF. Using Q1 as the reference group, the odds ratios for AF prevalence in Q4 were 1.35 (95% confidence interval [CI] 1.07-1.73) and 1.59 (95% CI 1.20-2.12) for 24-h estimated urinary Na/K ratio and estimated 24-h sodium excretion, respectively. Estimated 24-h potassium excretion was not associated with AF prevalence.

Conclusions: AF prevalence was positively associated with the urinary Na/K ratio and estimated 24-h urinary sodium excretion, but not with estimated 24-h urinary potassium excretion. Although further prospective studies are warranted, the findings of this study suggest that salt intake may be a modifiable risk factor for AF.