A proposed interval for evaluation of renal function during anticoagulation therapy using direct oral anticoagulants in patients with atrial fibrillation

Direct oral anticoagulants (DOACs) have been used to prevent cardiogenic embolism in patients with atrial fibrillation (AF). No evidence has been established for the follow-up renal function evaluation intervals. We hypothesized that a proposed follow-up interval of renal function can be estimated by patient's baseline characteristics including creatinine clearance (CCr).

We conducted a single-center retrospective study at Kindai University Hospital from May 2011 to December 2017. Patients were screened and they were enrolled if baseline CCr of ≥50 mL/min. To provide a periodical synchronization for measurements of CCr in all patients, these were evaluated at four different time points (approximately at 3, 6, 9, and 12 months). Primary endpoint was defined as a CCr value of <50 mL/min during the follow-up period. We analyzed associations between the cumulative risk for renal endpoint and baseline characteristics by the Kaplan-Meier method and the Cox proportional hazards model.

Renal endpoint was associated with age (95% CI: 0.07 to 0.21, p<0.01), body weight (95% CI: -0.09 to -0.01, p<0.01), CCr (95% CI: -0.18 to -0.07, p<0.01), and CHA2DS2-VASc score (95% CI: 0.14 to 0.63, p<0.01). Combining baseline CCr of <60 mL/min and other risk factors, acceptable intervals for 5% risk levels were 78 days (age ≥75 years old), 100 days (CHA2DS2-VASc score of> 4 points), and 90 days (body weight <60kg), respectively. Under conditions of baseline CCr of <60 mL/min, age ≥75 years old, CHA2DS2-VASc score of> 4 points, or body weight <60 kg, an increased risk of renal endpoints is 4.85, 3.29, 1.24, 2.44 fold, respectively.

We propose a risk-stratified follow-up interval for renal evaluation in patients with AF and DOACs therapy according to a combination of baseline CCr and other risk factors.