Impaired Kidney Function and Atrial Fibrillation in Elderly Subjects

BackgroundImpaired kidney function is associated with increased risk for cardiovascular events. We evaluated whether kidney function is associated with atrial fibrillation (AF) risk in elderly persons.Methods and ResultsSubjects were participants in the Cardiovascular Health Study (CHS), a population-based cohort of ambulatory elderly. Measures of kidney function were cystatin C and creatinine-based estimated glomerular filtration rate (eGFR). Among the 4663 participants, 342 (7%) had AF at baseline and 579 (13%) developed incident AF during follow-up (mean 7.4 years). In unadjusted analyses, cystatin C quartiles were strongly associated with prevalent AF with a nearly 3-fold odds in the highest quartile compared with the lowest (HR = 1.19, 95% CI [0.80-1.76] in quartile 2; HR = 2.00, 95% CI [1.38-2.88] in quartile 3; and HR = 2.87, 95% CI [2.03-4.07] in quartile 4). This increased risk for prevalent AF remained significant after multivariate adjustment. The risk for incident AF increased across cystatin C quartiles in the unadjusted analysis (HR = 1.37, 95% CI [1.07-1.75] in quartile 2; HR = 1.43, 95% CI [1.11-1.84] in quartile 3; and HR = 1.88, 95% CI [1.47-2.41] in quartile 4); however, after multivariate adjustment, these findings were no longer significant. An estimated GFR <60 mL·min·1.73 m2 was associated with prevalent and incident AF in unadjusted, but not multivariate analyses.ConclusionsImpaired kidney function, as measured by cystatin C, is an independent marker of prevalent AF; however, neither cystatin C nor eGFR are predictors of incident AF.