Clinical Characteristics, Patterns of Use, and incidence of Adverse Events in Patients With Nonvalvular Atrial Fibrillation Treated With Oral Anticoagulants in Colombia

Abstract

Purpose: The aim was to analyze the characteristics, treatment patterns, and clinical outcomes of Colombian patients with non-valvular atrial fibrillation (NVAF) under treatment with oral anticoagulants (OAs).

Patients and methods: Retrospective cohort in patients with NVAF identified from a drug dispensing database, aged ≥18 years, with first prescription of an OA (index) between January/2013 and June/2018, and a follow-up until June/2019. Data from the clinical history, pharmacological variables, and outcomes were searched. International Classification of Diseases-10 codes were used to identify the patient sample and outcomes. Patients were followed until a general composite outcome of effectiveness (thrombotic events), bleeding/safety or persistence (switch/discontinuation of anticoagulant) events. Descriptive and multivariate analyzes (Cox regressions comparing warfarin and direct oral anticoagulants-DOACs) were carried out.

Results: A total of 2076 patients with NVAF were included. The 57.0% of patients were women and the mean age was 73.3±10.4 years. Patients were followed for a mean of 2.3±1.6 years. 8.7% received warfarin before the index date. The most frequent OA was rivaroxaban (n=950; 45.8%), followed by warfarin (n=459; 22.1%) and apixaban (n=405; 19.5%). Hypertension was present in 87.5% and diabetes mellitus in 22.6%. The mean CHA₂DS₂-VASc Score was 3.6±1.5. The 71.0% (n=326/459) of the warfarin patients presented the general composite outcome, and 24.6% of those with DOACs (n=397/1617). The main effectiveness and safety outcomes were stroke (3.1%) and gastrointestinal bleeding (2.0%) respectively. There were no significant differences between patients with warfarin and DOACs regarding thrombotic events (HR: 1.28; 95% CI: 0.68-2.42), but warfarin was associated with higher bleeding/safety events (HR: 4.29; 95% CI: 2.82-6.52) and persistence events (HR: 4.51; 95% CI: 3.81 -5.33).

Conclusion: The patients with NVAF in this study were mainly older adults with multiple comorbidities. Compared to warfarin, DOACs were found to be equally effective, but safer and had a lower probability of discontinuation or switch.

Keywords: anticoagulation; direct oral anticoagulant; non-valvular atrial fibrillation; pharmacoepidemiology; real-world study; warfarin.