Factors Associated with Variation in Time in Therapeutic Range in Two Anticoagulation Clinics in Brazil

Abstract

Background: Time in therapeutic range (TTR) plays an important role in the effectiveness of anticoagulant therapy with vitamin K antagonists.Objective: To identify factors associated with variation in TTR. Methods:The study sites were anticoagulation clinics at two university hospitals in Minas Gerais, with a total of 1357 patients studied. TTR was calculated using the Rosendaal method. Binary logistic regressions were carried out with the study variables, followed by multiple regression with those that were significant for the model, adopting a significance level of 5%. Results:The outpatient clinics presented different values in mean TTR; one corresponded to the expected percentage, while the other did not. Multiple regression identified the variable male sex as a protective factor in relation to TTR < 60% (odds ratio [OR]: 0.42; p = 0). Conclusion:The identification of variables associated with inadequate TTR contributes to identifying weaknesses in the care process and implementing improvement actions in the hospitals studied.