Usual On-therapy Ranges of Drug Concentrations in Patients with Atrial Fibrillation Treated with Direct Oral Anticoagulants: A Systematic Review and Meta-analysis.

Background:  Although most patients with atrial fibrillation (AF) receiving a direct oral anticoagulant (DOAC) do not require drug concentration measurements, there are situations where such information could be useful. Existing guidance documents provide usual on-therapy ranges for drug concentrations, but these have important limitations.

Methods:  This is a systematic review and meta-analysis of studies reporting trough and peak levels of DOAC regimens approved for stroke prevention in AF.

Apixaban for Stroke Prevention in Atrial Fibrillation: Why are Event Rates Higher in Clinical Practice than in Randomized Trials?-A Systematic Review.

Background:  Recent reports suggest an important contribution from frequent off-label use of apixaban 2.5 mg twice daily to the higher rates of thromboembolic events observed in observational studies (OSs) relative to in randomized controlled trials (RCTs), and consequently, advocate against such use in all patients.

Objectives:  To examine factors contributing to the higher thromboembolic event rates, we estimated the prevalence of off-label use in contemporary practice, and compared patient characteristics and rates of stroke/systemic embolism, major bleeding, and mortality by apixaban dose and by study design in a systematic review and meta-analysis.