Quality of oral anticoagulation control in Chinese patients with non-valvular atrial fibrillation: a prospective controlled study

Objective The sex, age, medical history, treatment, tobacco use, race risk (SAMe-TT2R2) Score; the sex, age, medical history, treatment, tobacco use, genotype combination (SAMe-TT(2)G(2)) Score; and the so-called modified SAMe-TT(2)R(2)scores have been proposed to predict the anticoagulation quality for patients with non-valvular atrial fibrillation (NVAF). The data from a prospective controlled study is used to validate the SAMe-TT(2)R(2)and SAMe-TT(2)G(2)scores in Chinese NVAF patients treated with warfarin and to evaluate the association of factors with time in therapeutic range (TTR) to predict the quality of oral anticoagulation control. Methods A total of 379 patients with NVAF under warfarin treatment for a three-month follow-up were included in this prospective, multicenter study. The quality of oral anticoagulation control was evaluated by the TTR. The TTR was dichotomized for binary logistic regression analysis, using a cutoff point for classification as an inadequate (TTR < 65.0%) control. Results The 379 NVAF patients had a mean TTR of 58.35 +/- 26.33% and median SAMe-TT(2)R(2)and SAMe-TT(2)G(2)scores of 3 and 2, respectively. The discrimination performances of the SAMe-TT(2)R(2)and SAMe-TT(2)G(2)scores for inadequate anticoagulation control (TTR < 65.0%) were poor (c-index < 0.60). The gene frequency ofCYP2C9*3was 3.2% and that ofVKORC1-1639 G > Awas 89.3%. Genetic variation ofCYP2C9*3andVKORC1-1639 G > Adid not affect TTR after initial treatment. The condition TTR < 65.0% was associated with an age below 60 without genotype-guided warfarin dose initiation and concomitant torasemide. Conclusions A warfarin-dosing algorithm used for initial treatment of patients older than 60 helps to achieve a better quality of oral anticoagulation control, whereas concomitant torasemide can produce a negative effect. These findings provide useful information for future investigations on the quality of oral anticoagulation control in Chinese anticoagulation clinical practice.