Kidney function and the risk of heart failure in patients with new-onset atrial fibrillation

Heart failure (HF) is the most common complication of patients with atrial fibrillation (AF), but possible risk factors or health consequences are not well described. Low kidney function is a risk factor for both AF and HF. We evaluated estimated glomerular filtration rate (eGFR) as a predictor of HF in patients with AF, and then quantified the adverse health outcomes associated to incident HF.

This is an observational analysis of 19,662 adults without a previous history of HF who had new-onset AF in Stockholm healthcare (Sweden) during 2007-2011. During a median of 713 (IQR 281-1253) days of follow up, 3342 (16.4%) patients developed HF, with incidence rate of 7.4 per 100-person-years (95% CI 7.2-7.7). In Cox regression, eGFR was linearly associated with subsequent HF risk. Compared to eGFR≥60 ml/min/1.73 m², patients with eGFR 30-59 and eGFR<30 ml/min/1.73 m² had 13% (HR 1.13; 95% CI 1.04-1.23) and 53% (HR 1.53; 1.25-1.88) higher risk of HF. Results were consistent across various pre-specified subgroups and after excluding early events. Compared to non-HF, developing HF (as a time-varying exposure) was associated with a 5-fold (HR 5.05; 4.07-6.28) higher risk of subsequent kidney function decline, a 1.5 times higher risk of stroke (HR 1.54; 1.35-1.76), and a doubling in the risk of myocardial infarction (HR 2.21; 1.87-2.62) and death (HR 2.17; 2.01-2.33).

In patients with AF, low kidney function associates with the risk of HF. Developing HF heightened the subsequent risk of kidney function decline, cardiovascular event and death.