Low-dose warfarin for atrial fibrillation

Low-dose warfarin is less effective than adjusted-dose warfarin for prevention of thrombotic events in atrial fibrillation.

A systematic review including 4 studies with a total of 2,753 subjects was abstracted in DARE. The reported fixed low dose ranged from 0.5 to 3 mg/day. The target International Normalised Ratio (INR) was 1.1 to 1.6 for the low dose and 2 to 3.5 for the adjusted dose. Adjusted-dose warfarin reduced the risk of all thrombotic events compared with low-dose warfarin; the pooled RR was 0.50 (95% CI: 0.25 to 0.97, P=0.041). There was no statistically significant heterogeneity (P=0.56). Adjusted-dose warfarin tended to decrease ischaemic stroke compared with low-dose warfarin. However, this result was not statistically significant (RR 0.46, 95% CI: 0.2 to, 1.07, P=0.071). There was no difference in haemorrhagic death between the two treatments; the RR was 0.97 (95% CI: 0.27 to 3.54). Although mini- dose warfarin tended to reduce the risk of major haemorrhage, this was not statistically significant (RR 1.23, 95% CI: 0.67 to, 2.27, P=0.51).

Ədəbiyyat

1. Perret-Guillaume C, Wahl DG. Low-dose warfarin in atrial fibrillation leads to more thromboembolic events without reducing major bleeding when compared to adjusted-dose--a meta-analysis. Thromb Haemost 2004 Feb;91(2):394-402.