Factors associated to adequate time in therapeutic range with oral vitamin K antagonists in Tunisia

The quality of chronic anticoagulation and predictor factors of poor anticoagulant control in patients under acenocoumarol were unknown in North Africa.

It is an observational study, carried out between November 2015 and November 30, 2016. The international normalized ratio (INR) values were prospectively obtained, and TTR was calculated using the Rosendaal method.

Overall, 215 patients were included in this study, with a mean age of 63±0,8 years. The prevalence of poor anticoagulation control was 78.1%; 95% CI [72.2-83.2] (168 patients with TTR less than 65%). The median TTR with the Rosendaal method was 44.4%. After multivariate adjustment, variables significantly associated with adequate anticoagulation level were: history of ischemic stroke (Adjusted OR equal to 4.3, 95% CI: 1.4-12.9), associated prescription of antiplatelet therapy (Adjusted OR equal to 3.5, 95% CI: 1.1-11.2), daily prescribed dose of coumarins less than 6 mg (Adjusted OR equal to 6.4, 95% CI: 1.1- 36) and lower risk of bleeding assessed as HAS-BLED score (Adjusted OR: 0.5, 95% CI: 0.3-0.8).

The quality of anticoagulation management with VKA among outpatients who received acenocoumarol was suboptimal. Strategies should be undertaken by clinicians and patients to improve the quality of anticoagulation, to address challenges to adverse cardiovascular outcomes in individuals treated with chronic anticoagulation.