Atrial fibrillation (AF) and chronic kidney disease share risk factors and pathophysiologic mechanisms, suggesting that two conditions have close relationships.

This is a prospective community-based observational cohort study including 235,818 subjects based upon a voluntary annual health check-up program in Japan. We studied the association of kidney dysfunction at entry with subsequent new-onset AF and the association of AF at entry with the development of kidney disease.

During a follow-up of 5.9 ± 2.4 years, AF developed in 2947 subjects (1.3%). Baseline serum creatinine and estimated glomerular filtration rate (GFR) were associated with risk of subsequent AF. The HRs (95% CI) for AF were 1.32 (1.08-1.62) and 1.57 (0.89-2.77) for GFR 30 to 59 and <30 mL/min per 1.73 m², respectively. The effect of kidney disease on risk of new-onset AF remained significant in subjects without treated hypertension or diabetes. During the follow-up, 7791 subjects (3.3%) developed kidney dysfunction (GFR <60 mL/min per 1.73 m²), and 11 307 subjects (4.9%) developed proteinuria. Atrial fibrillation at entry was associated with development of kidney dysfunction (HRs [95% CI], 1.77 [1.50-2.10]) and proteinuria (HR [95% CI], 2.20 [1.92-2.52]). The association persisted in subjects without treated hypertension or diabetes.

Kidney dysfunction increased the risk of new onset of AF, and AF increased the risk of development of kidney disease. This finding supports the concept that the two conditions share common abnormal molecular signaling pathways contributing to their pathogenesis.