Estimated glomerular filtration rate within the normal or mildly impaired range and incident non-valvular atrial fibrillation: Results from a population-based cohort study

Background Lower estimated glomerular filtration rate, in particular in the significant renal impairment range (estimated glomerular filtration rate <60 ml/min/1.73 m²), is associated with incident atrial fibrillation. This association is less established within the normal or mildly impaired estimated glomerular filtration rate range. Methods Using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate formula, we identified ambulatory adults (>22 years old) without rheumatic heart disease or prosthetic valves and with 60 ml/min/1.73 m²<estimated glomerular filtration rate<130 ml/min/1.73 m² in their index visit, for incident, newly-diagnosed atrial fibrillation. We analyzed cohorts with and without prior cardiovascular disease. Results Over a mean follow-up of 104 months and >10 m patient-years of follow-up (-1/475% <60 years old, -1/457% females), >65,000 individuals had ≥1 atrial fibrillation event (incident atrial fibrillation rate 5.1% and 5.8% excluding or including prior cardiovascular disease, or 49 and 55 per 10,000 patient-years, respectively). In both cohorts, individuals with versus without incident atrial fibrillation had lower mean estimated glomerular filtration rate (-1/483 versus 95 ml/min/1.73 m²). Adjusting for age, gender, hypertension, and diabetes mellitus, overall a 10 ml/min/1.73 m² decrease in estimated glomerular filtration rate was independently associated with a mean increase in incident atrial fibrillation of 1.5% and 2.4% in the cohorts excluding or including prior cardiovascular disease, respectively (p < 0.001 for both). However, a graded association between lower estimated glomerular filtration rate and atrial fibrillation was observed in the 90-130 ml/min/1.73 m² range, whereas a blunted association was observed in the 60-90 ml/min/1.73 m² range. Conclusion Within the 60 ml/min/1.73 m²< estimated glomerular filtration rate < 130 ml/min/1.73 m² range, lower estimated glomerular filtration rate is independently associated with incident non-valvular atrial fibrillation in adults without prior atrial fibrillation, mainly attributed to a graded association within the 90-130 ml/min/1.73 m² range.