Direct oral anticoagulation and severe obesity – One size fits all?

Abstract

Oral anticoagulation is obligatory in patients with atrial fibrillation (AF) to prevent thromboembolic stroke. Direct direct oral anticoagulants (DOAC) exhibit improved safety over Vitamin K antagonists, but any interference in haemostasis can impact on bleeding. Optimal anticoagulation remains challenging particularly in patients with co-morbidities. International Society of Thrombosis and Haemostasis (ISTH) guidelines recommend avoiding DOAC in patients with severe obesity, and systematic data on individual DOAC drug concentrations, clinical efficacy and safety in relation to body weight are lacking. A new study now provides reassurance that DOAC are safe and effective in a real-world cohort of morbidly obese patients, going some way to fill the knowledge gap pertaining to optimal management of concomitant obesity and AF.

Emulating a target trial to assess effect modification: an application to obesity in the comparative effectiveness and safety of apixaban versus warfarin in non-valvular atrial fibrillation using electronic health records

“…The similar comparative treatment response across BMI groups in the study was contrary to previous suggestions in the literature that obesity plays a major role in treatment effects of anticoagulants 18,19 .…”

“…For apixaban, a lower dose is used in underweight patients but there is no dose modification for obese patients possibly leading to sub-optimal dosing. Recent literature identified a gap in the evidence for optimal dosing of patients with increasing body weight which results in altered haemostasis and increased thrombosis 18,19 .…”

Recent highlights on thrombosis and hemostasis from the International Journal of Cardiology: Heart & Vasculature

“…Reassuringly, the authors found no significant difference in terms of mortality, ischemic stroke, and major bleeding between the high risk morbidly obese group and the general patient population under DOAC treatment. The accompanying editorial [15] discussed the potential mechanistic background, the clinical implications and the gaps in knowledge in this important context.…”

Recent highlights from the International Journal of Cardiology Heart & Vasculature on challenges for adequate stroke prevention in patients with atrial fibrillation

“…Despite the retrospective study design and the relatively small sample size (n = 135), the key message that DOAC therapy is safe even in the morbidly obese patients is reassuring, given that current International Society of Thrombosis and Haemostasis (ISTH) guidelines recommend avoiding DOAC in these patients. The implications are discussed in further detail in an accompanying editorial [16] .…”