Appropriateness of dabigatran dosing in patients with nonvalvular atrial fibrillation (NVAF): A retrospective study conducted in a tertiary care university hospital in the eastern province of Saudi Arabia

BACKGROUND: Establishment of thromboembolism prevention remains a challenge despite the widespread consensus that thromboprophylaxis safely reduces patient morbidity and mortality. Dabigatran is a nonvitamin K antagonist oral anticoagulant (NOAC) which reduces the risk of thromboembolism. Proper dosing is important to achieve the maximum prophylactic benefit with a maintained safety profile. OBJECTIVE: To evaluate the appropriateness of dabigatran dosing for stroke and systemic embolism prevention in patients with nonvalvular atrial fibrillation (NVAF). METHODS: This is a retrospective cohort study of adults with NVAF. The data were collected from the electronic filing system of the hospital. Patients receiving dabigatran therapy were divided into two treatment groups according to the dose of dabigatran received. The indications for dabigatran as an oral direct anticoagulant, including age, risk of bleeding, creatinine clearance (CrCl), were collected. Appropriateness of dose reduction included any of the following factors: HAS-BLED score >2 points, age ≥75 years, or CrCl of 30–50 mL/min. The two groups were evaluated according to dose appropriateness. RESULTS: Dabigatran dose of 110 mg was found to be inappropriately low in a large number of patients (31.3%). Multivariate regression analysis showed significant association of age and dose appropriateness (p < 0.001). CONCLUSION: This study revealed inappropriate prescription of reduced doses of dabigatran in a large number of patients. Age was identified as the main driving factor for underdosing. Physicians’ and pharmacists’ awareness regarding this type of high-risk medication should be improved to ensure appropriate and safe use of this commonly used drug.