The role of anticoagulation in stroke prevention: selection of the appropriate NOAC dose
Debreceni Egyetem, Általános Orvostudományi Kar, Neurológiai Tanszék, Debrecen
Dr. Oláh László egyetemi tanár, 4032 Debrecen, Móricz Zs. krt. 22. E-mail: email@example.com
Atrial fibrillation (AF) in the aging population is becoming more prevalent and by increasing the risk of stroke fivefold, it contributes significantly to the large number of strokes. The stroke risk in AF can be substantially reduced by the use of oral anticoagulants. New types of oral anticoagulants (NOACs) emerged in the last decade have several advantages over warfarin. Although no frequent dose adjustment is required for NOACs, decisions to prescribe the available standard or reduced dose should be made.
Real world data have shown that patients with AF in the every-day practice receive a reduced dose of NOACs much more frequently (36-64%) than in the clinical trials. The efficacy and safety of on-label reduced-dose NOACs were similar to those of warfarin. However, apixaban had a lower risk of major bleeding, and dabigatran was associated with a lower risk of mortality compared with warfarin. The use of off-label NOAC doses is also not negligible: the prevalence of off-label underdose and overdose rates were 20% and 5%, respectively. Compared to on-label dosing, large meta-analyses showed that off-label use of the reduced-dose NOACs (underdosing) did not decrease the risk of major bleeding, but was associated with higher risk of thromboembolic events and mortality, i.e. underdosing was associated with reduced effectiveness without a safety benefit. Off-label use of the standard dose (overdosing) increased the risk of major bleeding and mortality and, contrary to expectations, did not reduce the risk of stroke.
This summary draws attention to the frequency of off-label dosing of NOACs and the potential hazards associated with inappropriate NOAC dosin