Quality of oral anticoagulation treatment in real-life practice and factors associated with optimal therapeutic response in elderly patients

Introduction. Oral anticoagulation therapy (OAT) is recommended in several cardiovascular disorders and is increasingly used in elderly patients. Obtaining a stable value of International Normalized Ratio (INR) within the target levels may however represent a difficult goal, in this population. Indeed, there is suggestion that out of range INR values are frequently seen in clinical practice. This fact may be associated with serious adverse events such as bleeding and thromboembolic disorders, which may be often fatal in elderly people. Aim of the present study was to evaluate the factors associated with an increased risk of out of range INR levels in this subgroup of patients. Methods. Consecutive patients admitted to the Emergency Department of two Italian Institutions were analyzed within two hours of their admission. Only patients 70 years or older were eligible for the study. Results. 242 patients were enrolled, 151 of whom (62.4%) with abnormal values. When comparing the characteristics of those within or outside the normal range, it appeared that the former had a higher educational level (27% vs 5%) and more frequently a duration of treatment longer than 5 years (62% vs 27%): OR=7.36; 95% C.I. 3.02-17.95; p < 0.0001, and OR=4.29; 95% C.I. 2.46-7.47; p < 0.0001, respectively. Discussion. The majority of patients in this sample of elderly patients seem unable to maintain optimal INR values. The risk seems higher in patients with a low level of education and with less than 5 year OAT.