April 2024
Does obesity modify efficacy of direct oral anticoagulants in atrial fibrillation?

Results from a pooled analysis of pivotal trials suggest preserved efficacy across a wide range of body weights and body-mass indices.

The prevalence of atrial fibrillation (AF) is higher among obese patients. Yet, there is concern about possible diminished efficacy and safety of direct oral anticoagulants (DOACs) for stroke prevention in AF in this at-risk group, as well as in underweight individuals. To date, subgroup analyses from individual trials have been underpowered to provide clear inferences. The current study used pooled individual participant data from randomised trials to examine the efficacy and safety of DOACs across the spectrums of body weight and body mass index (BMI).

Data were from about 58,000 patients participating in four pivotal trials comparing individual DOACs (dabigatran, rivaroxaban, apixaban and edoxaban) with vitamin K antagonists (VKAs) in AF. The investigators found that, compared with VKAs, DOACs were associated with reduction in risk for stroke or systemic embolism (hazard ratio, 0.80), which was similar across body weight and BMI strata. The association was observed in patients who were obese and also in those who were underweight (BMI below 18.5kg/m2 or body weight below 50kg). Use of DOACs was also associated with reduced risk for intracranial haemorrhage, which was also consistent across body weight and BMI strata.

Comment: These results are reassuring for management of both underweight and overweight patients with AF. That said, I would still have reservations about prescribing DOACs in the small minority of patients with BMI above 45kg/m2 or body weight above 150kg due to their underrepresentation in the pivotal trials. After all, warfarin works and can be adjusted as needed.

Behnood Bikdeli, MD, MS, Associate Physician, Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Boston; Instructor in Medicine, Harvard Medical School, Boston; Investigator, Yale New Haven Hospital Center for Outcomes Research and Evaluation, New Haven, USA.

Patel SM, et al. Efficacy and safety of non- vitamin-K antagonist oral anticoagulants versus warfarin across the spectrum of body mass index and body weight: an individual patient data meta-analysis of four randomized clinical trials of 58464 patients with atrial fibrillation. Circulation 2024 Jan 24; e-pub (https://doi.org/10.1161/ CIRCULATIONAHA.123.066279).

This summary is taken from the following Journal Watch title: Cardiology.