Safety of low-dose dabigatran in patients with atrial fibrillation and mild renal insufficiency.
Dabigatran etexilate (DE), an effective direct oral anticoagulant for patients with atrial fibrillation (AF), should be carefully used in patients with renal insufficiency. Data on the safety of DE in Japanese "real world" patients with mildly impaired renal function are limited. We hypothesized that low-dose DE (110mg, twice daily) could be safely used in Japanese AF patients with mildly impaired renal function compared to those with preserved renal function. One hundred ninety-six consecutive AF patients taking low-dose DE were retrospectively enrolled in this study, and were divided into two groups: preserved creatinine clearance (CCr ≥50ml/min; n=127) and reduced CCr (30-49ml/min; n=69). Baseline characteristics including CHADS2, CHA2DS2-VASc, and HAS-BLED scores were evaluated. Activated partial thromboplastin time (aPTT) was measured as a surrogate marker of the anticoagulant activity of DE, which was evaluated at 661 time points in total and the data were divided into five time windows after the last DE intake. The incidence of bleeding complications was compared between the two groups of reduced and preserved CCr. Reduced CCr group showed higher age (76.9±6.3 years vs. 67.6±6.7 years), higher CHADS2 (2.6±1.4 vs. 1.8±1.2), higher CHA2DS2-VASc (4.3±1.6 vs. 3.2±1.6), and higher HAS-BLED (2.3±1.0 vs. 2.0±1.0) scores in comparison with preserved CCr group (p<0.01, respectively). There was no difference in aPTT over the entire time windows between the two groups. The incidence of total bleeding events was not significantly different between the two groups (reduced vs. preserved CCr=2/69 vs. 2/127). Low-dose DE was safe in AF patients with mildly reduced CCr.