Kidney function associated with risk for thromboembolism in atrial fibrillation

Proteinuria and glomerular filtration rate were associated with an increased rate of thromboembolism in patients with nonvalvular atrial fibrillation, according to data from the Anticoagulation and Risk Factors in Atrial Fibrillation study. The association was independent of other risk factors.

The study included 13,535 patients aged 18 years or older with nonvalvular atrial fibrillation and no prior kidney transplant. The researchers estimated glomerular filtration rates and proteinuria and obtained information on patient characteristics, warfarin use and thromboembolic events.

Of the subset with known kidney function at study entry, 18.5% of men and 25.9% of women had a reduced eGFR of between 45 mL×min^–1×1.73m^–2 and 59 mL×min^–1×1.73m^–2 and 10.6% of men and 12.9% of women had an eGFR <45 mL×min^–1×1.73m^–2. Of those with known baseline kidney function, 0.9% of men and 0.7% of women met the criteria for end-stage renal disease at entry.

The researchers reported 676 incident thromboembolic events among 10,908 patients during 33,165 person-years off of anticoagulation. After adjusting for known stroke risk factors, the researchers reported proteinuria was associated with a 54% increase in the risk for thromboembolism (95% CI, 1.29-1.85).

A progressively lower rate of eGFR was associated with a graded increased risk for stroke. Compared with an eGFR ≥60 mL×min^–1×1.73m^–2, eGFR between 45 mL×min^–1×1.73m^–2 and 59 mL×min^–1×1.73m^–2 was associated with a RR of 1.16 (95% CI, 0.95-1.40) and eGFR <45 mL×min^–1×1.73m^–2 was associated with a RR of 1.39 (95% CI, 1.13-1.71).

Go AS. Circulation. 2009;doi:10.1161/CIRCULATIONAHA.108.816082