Obese patients with atrial fibrillation are more efficiently protected from thrombosis under warfarin or xabans compared to non-obese patients; a systematic review and Meta-analysis of six randomized controlled trials
Lazaros Karatisidis a); Konstantinos Zagoridis a); Theodoros Mprotsis b); Christina Misidou a); Aikaterini Pentidou a); George Vrachiolias a); Zoi Bezirgianidou a); Emmanouil Kontomanolis c); Emmanouil Spanoudakis a).
a) Department of Hematology, Democritus University of Thrace, Medical School, Alexandroupolis, Greece
b) Department of Biomathematics, University of Thessaly, School of Medicine, Greece
c) Department of Obstetric Gynecology, Democritus University of Thrace, Medical School, Alexandroupolis, Greece
Abstract
Introduction
Recommendations about proper anticoagulation in obese patients, body mass index (BMI) > 30 kg/m2, are not yet clearly defined. Obese patients were included in randomized controlled trials comparing new anticoagulants (NOACs) with warfarin in patients with atrial fibrillation or thromboembolism.
Methods
We performed a medline search entering proper criteria and finally 6 post-hoc analysis of RCTs, reporting outcome according to BMI, were included in this meta-analysis. Two major outcomes were considered end points in our meta-analysis; thrombosis, including ischemic cerebral events (transient or not) and venous thrombosis (DVD) /pulmonary embolism (PE) and bleeding, including major bleeding and clinically relevant non-major bleeding.
Results
In the NOACs treated group, thrombosis occurred less frequently in obese vs non-obese patients; RR and 95 % CI 0,75 (0,58–0,97), p = 0,03, while low heterogeneity was observed (I2= 40 %). In the warfarin treated subgroup there was statistically significant difference with less thrombotic events occurring in the obese vs non-obese patients; RR and (95 % CI) 0,80 (0,66-0,98), p = 0,03, and heterogeneity was low (I2 = 24 %).
This protective effect called the obesity paradox is limited to obese patients anticoagulated for non-valvular atrial fibrillation (NVAF); RR (95 % CI) was 0,70 (0,58–0,85) p = 0,03 and I2 = 24 %. Bleeding events were similar under both NOACs and warfarin in obese vs non-obese analysis.
Conclusions
Obese patients anticoagulated for NVAF with either standard dose of xabans or INR guided warfarin are more efficiently protected against thrombosis compared to non-obese patients.