RESUMEN
Objective:To investigate the relationship between early international normalized ratio(INR)and overanticoagulation in elderly patients with atrial fibrillation(AF)treated with Warfarin, and to evaluate its clinical value in predicting overanticoagulation.Methods:A total of 470 elderly patients with AF treated with Warfarin for anticoagulation were enrolled retrospectively.INR was detected in the morning of the next day after 3 days and 7 days of Warfarin treatment.According to whether INR was greater than 3.0 after 7 days of Warfarin treatment, the patients were divided into over-anticoagulation group(n=107)and non-over-anticoagulation group(n=363). The general clinical data of the two groups were analyzed.The receiver operating characteristic curve(ROC)was used to evaluate the value of 3-day INR(early INR)level in predicting overanticoagulation.Logistic regression was used to analyze the factors related to overanticoagulation in elderly AF patients receiving Warfarin treatment.Results:The age, initial warfarin dose, early INR and serum aspartate transferase level in the over-anticoagulation group were higher than those in the non-over-anticoagulation group( P<0.05 for all). The proportions of patients with initial Warfarin dose≥2.5 mg, age≥70 years old, body weight≤65 kg, valvular atrial fibrillation, hypoproteinemia, abnormal liver function, and combined use of antibiotics were higher in the over-anticoagulation group than those in the non-over-anticoagulation group( P<0.05 for all). The body weight, serum albumin level and the proportion of diabetes mellitus in the over-anticoagulation group were lower than those in the non-over-anticoagulation group( P<0.05). ROC curve showed that the area under the curve(AUC)of early INR in predicting over-anticoagulation was 0.927(95% CI: 0.900-0.949, P<0.0001), the sensitivity was 82.86% and the specificity was 88.43%, the optimal cutoff value for predicting overanticoagulation was INR≥1.66.Multiple Logistic regression analysis showed that early INR level≥1.66( OR=33.871, P<0.001), initial warfarin dose≥2.5 mg( OR=17.062, P=0.011), body weight≤65 kg( OR=2.824, P=0.002), age≥70 years old( OR=2.678, P=0.003), and abnormal liver function( OR=2.091, P=0.022)were related factors for over-anticoagulation in elderly patients with atrial fibrillation. Conclusions:Early INR level is closely related to overuse of anticoagulation in elderly AF patients receiving Warfarin treatment, which can be regarded as a predictor of overuse of anticoagulation.Early INR level in elderly AF patients receiving warfarin treatment should be monitored to reduce the incidence of anticoagulant overuse.