At present, there are few studies on the stability of warfarin anticoagulation therapy. The main evaluation method is SAMe-TT2R2 score, but it has obvious limitations and is not applicable to non-white population. Previous studies have shown that platelet distribution width (PDW) and left atrial diameter (LAD) are closely related to time within therapeutic range (TTR). Whether they can be incorporated into the existing scoring system and improved is worthy of clinical reflection.

To explore the predictive value of modified SAMe-T-PDW2-LAD2 score for the percentage of TTR of common international normalized ratio (INR) for the stability of warfarin anticoagulation therapy.

A total of 164 patients with persistent nonvalvular atrial fibrillation who were treated with warfarin anticoagulation in Jiujiang NO.1 People's Hospital from January 2021 to June 2023 were selected as the research objects. TTR≥65% was defined as high quality anticoagulation. TTR<65% was defined as substandard, that is, the stability of warfarin anticoagulation therapy was not high-quality. According to the above criteria, the patients were divided into two groups: TTR≥65% group (TTR≥65%, 46 cases) and TTR<65% group (TTR<65%, 118 cases). The modified SAMe-T-PDW2-LAD2 score retained the four parameters of gender, age, comorbidities and combined medication in the previous SAMe-TT2R2 score, and the two parameters of race and smoking were deleted. "Increased PDW" and "increased LAD" were replaced by 2 points respectively. The above parameters were collected and compared between the two groups. Binary Logistic regression analysis was used to explore the influencing factors of stable TTR target in warfarin anticoagulation therapy. Receiver operating characteristic (ROC) curves of SAMe-TT2R2 score and modified SAMe-T-PDW2-LAD2 score were plotted to evaluate the TTR target stability of warfarin anticoagulation therapy.

Single factor analysis showed that there were significant differences in age, combined with heart failure, combined with hyperlipidemia, smoking, increased PDW and increased LAD between the two groups (P<0.05). Binary Logistic regression analysis showed that age (OR=0.882, 95%CI=0.812-0.958, P=0.003), increased PDW (OR=0.443, 95%CI=0.282-0.697, P<0.001), and increased LAD (OR=0.031, 95%CI=0.001-0.853, P=0.040) were the influencing factors of achieving stable TTR target on warfarin anticoagulation therapy. There were significant differences in TTR and TTR reaching the target rate between groups with different scores of SAMe-TT2R2 score (P<0.05). The TTR of scores 6 and 7 groups was higher than that of scores 2, 3, 4 and 5 groups (P<0.05). The TTR target rate in the score 7 group was higher than that in the score 2, 3, 4, 5, and 6 groups (P<0.05). There were significant differences in TTR and TTR reaching the target rate among different score groups of modified SAMe-T-PDW2-LAD2 score (P<0.05). The TTR of scores 3, 4, 5, 6, and 7 groups was lower than that of scores 0, 1, and 2 groups (P<0.05). The TTR target rate in the integral 2 group was higher than that in the integral 0, 1, 3, 4, 5, 6, and 7 groups (P<0.05). ROC curve results showed that the area under the ROC curve (AUC) of SAMe-TT2R2 score for evaluating the stability of warfarin anticoagulation therapy TTR target was 0.803 (95%CI=0.737-0.868), the best cut-off value was 5.5, the sensitivity was 1, and the specificity was 0.508. The AUC of modified SAMe-T-PDW2-LAD2 score was 0.814 (95%CI=0.751-0.877), the best cut-off value was 2.5, the sensitivity was 0.848, and the specificity was 0.737.

Age, increased PDW and increased LAD are the influencing factors of achieving stable TTR target in warfarin anticoagulation therapy. There are many limitations of SAMe-TT2R2 score in evaluating the stability of warfarin anticoagulation therapy. The modified SAMe-T-PDW2-LAD2 score has better clinical application value in evaluating the stability of warfarin anticoagulation therapy.