Assessment of Anticoagulation Management Practices Among Patients with Atrial Fibrillation in Abuja

Atrial fibrillation is the most common sustained cardiac arrhythmia and a major risk factor for stroke, and optimising anticoagulation therapy is essential for stroke prevention in this population. This study assessed anticoagulation management practices and international normalised ratio control among patients with atrial fibrillation receiving warfarin at a cardiology outpatient clinic in Abuja, Federal Capital Territory. A retrospective cross-sectional study was conducted using medical records and pharmacy dispensing data for 140 atrial fibrillation patients on warfarin for at least six months. Time in therapeutic range was calculated using the Rosendaal linear interpolation method. Data on monitoring frequency, dose adjustments, and adverse events were extracted. Results showed that mean time in therapeutic range was 51.3 percent, well below the recommended target of 65 percent or above. Only 37.1 percent of patients achieved a TTR of 65 percent or more. Subtherapeutic INR values were more frequent than supratherapeutic levels, occurring in 38.6 percent of recorded INR measurements. Non-adherence to scheduled INR monitoring was reported in 46.4 percent of patients. Drug interactions with amiodarone and NSAIDs were the most common pharmacist-documented interferences with INR stability. The study recommends establishing a pharmacist-managed anticoagulation clinic, implementing patient self-monitoring of INR where feasible, and exploring direct oral anticoagulant therapy for eligible patients to improve stroke prevention outcomes.

Keywords: anticoagulation, atrial fibrillation, warfarin, INR control, Abuja