Anticoagulants' Safety and Effectiveness in General Practice: A Nationwide Prospective Cohort Study.

PURPOSE: Most real-world studies on anticoagulants have been based on health insurance databases or performed in secondary care. The aim of this study was to compare safety and effectiveness between patients treated with vitamin K antagonists (VKAs) and patients treated with direct oral anticoagulants (DOACs) in a general practice setting. METHODS: The CACAO study (Comparison of Accidents and their Circumstances with Oral Anticoagulants) is a multicenter prospective cohort study conducted among ambulatory patients taking an oral anticoagulant. Participants were patients from the study's cross-sectional phase receiving oral anticoagulants because of nonvalvular atrial fibrillation, for secondary prevention of venous thromboembolism, or both. They were followed as usual for 1 year by their general practitioners, who collected data on changes in therapy, thromboembolic events, bleeding, and deaths. All events were adjudicated by an independent committee. We used a propensity score and a Cox regression model to derive hazard ratios. RESULTS: Between April and December 2014, a total of 3,082 patients were included. At 1 year, 42 patients (1.7%) had experienced an arterial or venous event; 151 (6.1%) had experienced bleeding, including 47 (1.9%) who experienced major bleeding; and 105 (4.1%) had died. There was no significant difference between the VKA and DOAC groups regarding arterial or venous events, or major bleeding. The VKA group had a lower risk of overall bleeding (hazard ratio = 0.65; 95% CI, 0.43-0.98) but twice the risk of death (hazard ratio = 1.98; 95% CI, 1.15-3.42). CONCLUSIONS: VKAs and DOACs had fairly similar safety and effectiveness in general practice. The substantially higher incidence of deaths with VKAs is consistent with known data from health insurance databases and calls for further research to understand its cause.

Areas of improvement in anticoagulant safety. Data from the CACAO study, a cohort in general practice.

BACKGROUND: Real-world studies on anticoagulants are mostly performed on health insurance databases, limited to reported events, and sometimes far from every-day issues in family practice. We assess the presence of data for safe monitoring of oral anticoagulants in general practice, and compare patients' knowledge of taking an anticoagulant between vitamin K antagonists (VKA) and direct anticoagulants (DOAC), and the general practitioner's perception of their adherence to anticoagulation. METHODS: The CACAO study is a national cohort study, conducted by general practitioners on ambulatory patients under oral anticoagulant. In the first phase, investigators provided safety data available from medical records at inclusion. They also evaluated patients' knowledge about anticoagulation and graded their perception of patients' adherence. RESULTS: Between April and December 2014, 463 general practitioners included 7154 patients. Renal and hepatic function tests were respectively unavailable in 109 (7.5%) and 359 (24.7%) DOAC patients. Among patients with atrial fibrillation, 345 patients (6.9%) had a questionable indication of anticoagulant (CHA2DS2-Vasc<2). One hundred and thirty-three VKA patients (2.3%) and 70 DOAC patients (4.9%) answered they took no anticoagulant (p<0.0001). According to general practitioners' perception, 430 patients (6.1%) were classified as "not very" or "not adherent", with no difference between groups. CONCLUSIONS: Our results highlight the efforts needed to improve anticoagulant safety in daily practice: decreasing the rate of unknown biological data in patients with DOACs or the rate of patients with VKA with no strong indication of anticoagulation, and improving patient knowledge with regard to their anticoagulant. Patients' adherence seems highly over-estimated by the general practitioners. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02376777.