INR Control and Atrial Fibrillation in Primary Care in Spain (PAULA)

Vitamin K antagonists (VKAs) have traditionally been used for long-term prevention of thromboembolic complications in patients with atrial fibrillation (AF). Because of the variability in the dose response with VKAs and the narrow therapeutic window, monitoring the degree of anticoagulation is mandatory. The international normalized ratio (INR) provides a standardized measure of the VKA anticoagulant effect. The INR should be kept within a narrow range (therapeutic INR target 2.0-3.0) to control the intensity of anticoagulation. The primary objective of this study was to determine rates of INR control of patients with nonvalvular AF daily attended in primary care in Spain. PAULA is an observational retrospective/cross-sectional and multicenter study supported by the three main Spanish primary care scientific societies: Sociedad Española de Médicos de Atención Primaria (SEMERGEN), Sociedad Española de Medicina de Familia y Comunitaria (SEMFYC) and Sociedad Española de Médicos Generales y de Familia (SEMG). Patients aged ≥18 years old, with nonvalvular AF, treated with VKAs for at least one year in primary care were included in the study. To be included, at least 80% of INR values during the past 12 months should be available. Before inclusion, patients provided written consent. Clinical data (biodemographic data, comorbidities, treatments, and thromboembolic/bleeding risk) were recorded from the clinical history of patients at the moment of inclusion. INR values were taken from the previous 12 months of inclusion. Poor INR control was considered when percent time in therapeutic INR range (TTR) was \<65% (calculated by Rosendaal method) or \<60% by direct method (proportion of INR values). The study was approved by the ethics committee of hospital La Paz, Madrid. A total of 1,524 patients have been included in the study.