ICUSI questionnaire validation. Quality of anticoagulation in patients with atrial fibrillation treated with vitamin K antagonists

Abstract

Introduction and objectivesVitamin K antagonists (VKAs) are still widely used for stroke prevention in atrial fibrillation. However, the access to international normalised ratio (INR) determinations is sometimes difficult and the time in therapeutic range (TTR) is not always available. The aim of this study was to design and validate a simple and easy-to-use questionnaire that enables the identification of atrial fibrillation patients with poor quality of anticoagulation. MethodsThis is a national, multi-centre, observational, and cross-sectional study including consecutive non-valvular atrial fibrillation patients receiving VKA therapy and followed up at cardiology clinics. At inclusion, INR determinations during the last 6 months were analysed to determine the TTR and the ICUSI questionnaire was completed. A TTR < 65% was considered suboptimal. ResultsA total of 813 patients (55% men, 75±9 years old) were available for the analyses. The mean TTR was 62.2%±20.3% and 427 (52.5%) patients had a TTR < 65%. The final version of the ICUSI questionnaire included 4 questions and the mean ICUSI score was 1.19±1.17. The predictive ability of the ICUSI questionnaire for predicting TTR < 65% was moderate (c-index, 0.707; 95%CI, 0.670–0.740; P<.001). An ICUSI score of 1 showed a sensitivity of 80.8% and a specificity of 45.6%, whereas an ICUSI score of 2 showed a sensitivity of 43.2% and a specificity of 88.1%. ConclusionsThe ICUSI questionnaire has shown a good predictive performance for the identification of poor TTR in the absence of full access to the INR determinations in atrial fibrillation patients under VKA therapy.