Comparison of creatinine-based equations for estimating renal function for digoxin dose adjustment in patients with atrial fibrillation and heart failure.

The aim of this study was to determine an appropriate equation for estimating renal function to dose regulate the serum digoxin trough concentration to a target of <0.9 ng/ml in patients with atrial fibrillation (AF) and heart failure (HF). All patients received 0.125 mg oral digoxin daily. The estimated glomerular filtration rate by the Modification of Diet in Renal Disease (eGFR MDRD ) equation deindexed based on body surface area had the highest correlation with digoxin trough concentrations (r = -0.450) compared to the Cockcroft-Gault equation (r = -0.415) or deindexed eGFR based on the Chronic Kidney Disease Epidemiology Collaboration (eGFR CKD-EPI ) equation (r = -0.416). The median digoxin trough concentrations were 0.60, 0.77, 0.97 and 1.30 ng/ml in patients with a deindexed eGFR MDRD  ≥ 60, 45-59, 30-44 and < 30 ml/min, respectively. The deindexed eGFR MDRD is an appropriate equation for digoxin dose adjustment in patients with AF and HF.