The novel risk score model for predicting the poor anticoagulation control in patients with atrial fibrillation taking warfarin.

BACKGROUND

Previous trials have shown that the C-statistics of SAMe-TTR score in the prediction of suboptimal time in therapeutic range (TTR) is very low.

OBJECTIVES

To propose the novel risk score model for predicting the poor anticoagulation control in atrial fibrillation (AF) patients compared with the SAMe-TTR score.

METHODS

We prospectively recruited AF patients from 27 hospitals between 2014 and 2017 in the COOL AF Thailand registry. The poor anticoagulation control was defined as TTR <65%. Multivariate logistic regression analysis was performed for the prediction of poor anticoagulation control. The novel risk score model was then generated. Receiver operating characteristic (ROC) curve analysis was performed to calculate the C-statistics and to compare between the novel risk score model and the SAMe-TTR score. Net Reclassification Index (NRI) and Integrated Discrimination Index (IDI) were performed.

RESULTS

Of 3,461 patients, 2,233 patients taking warfarin having available TTR data were retrieved. There were 1,432 patients having poor anticoagulation control (TTR < 65%) and 801 patients having good anticoagulation control (TTR ≥ 65%). Symptomatic AF, diabetes, heart failure, and a history of bleeding were associated with increased risk while obesity, AF duration, and paroxysmal AF were associated with decreased risk of poor anticoagulation control. SHOB-DAF score was created. The C-statistics of SHOB-DAF score was greater than the SAMe-TTR score (0.584 vs 0.506, < 0.001). NRI of the SHOB-DAF score was 17.82% compared with the SAMe-TTR score.

CONCLUSIONS

SHOB-DAF score was the novel risk score which was better than the SAMe-TTR score in predicting poor anticoagulation control.