Coagulation

ISTH 2021: New guidelines on DOAC use in obese patients


New ISTH recommendations regarding the use of DOACs for VTE prevention suggest rivaroxoban or apixaban are among appropriate anticoagulant options regardless of high BMI or weight.

Previously, the 2016 guidance from the ISTH suggested not using DOACs in people with BMI >40 kg/m2 and weight >120 kg.

The new recommendations, presented at ISTH 2021 and published in the Journal of Thrombosis and Haemostasis, do not support use of dabigatran, edoxaban or betrixaban in patients with high BMI or body weight because of the limited clinical data.

Dr Karlyn Martin, Assistant Professor of Medicine in the Division of Hematology/Oncology at Northwestern University, Chicago told the Congress that most of the clinical data for individual DOACs which had become available was for rivaroxoban.

For example, a sub-analysis of the EINSTEIN DVT/PE studies, showed that hazard ratios for rivaroxaban vs enoxaparin/VKA were similar in all bodyweight and BMI categories. A high BMI was not associated with an increased risk of recurrent VTE during anticoagulation.

A recently published study of apixaban versus warfarin has shown a significantly lower risk of recurrent VTE and major bleeding with the DOAC in obese and morbidly obese VTE patients.

In a meta-analysis of trials with extremely high body weight patients, DOACs were non-inferior compared to warfarin with respect to VTE recurrence (OR 1.07, 95% CI 0.93–1.23).

Dr Martin said that small studies suggest obesity has no significant impact on peak and trough levels for apixaban and rivaroxaban although lower peak levels were seen with dabigatran.

“I think we need to be careful in how we interpret these. Therapeutic levels of DOACS remain unknown and have not been correlated with risk for clinical outcomes. So while reference DOAC levels represent expected or on-therapy ranges, they are not therapeutic targets,” she said.

“We suggest not to regularly follow peak or trough drug-specific DOAC levels given the lack of relation with clinical outcomes.”

She said that, consistent with 2016 guidance, any DOACs were appropriate in patients with BMI ≤ 40 kg/m2 or weight up to 120 kg.

The full guidance also provides recommendations for DOAC use in patients following bariatric surgery.

It said not to use DOACs for treatment or prevention of VTE in the acute setting after bariatric surgery because of concerns of decreased absorption and instead, to initiate such patients on parenteral anticoagulation in the early postsurgical phase..

“We suggest that switching to VKA or DOAC may be considered after at least 4 weeks of parenteral treatment, and if so, suggest obtaining a DOAC trough level to check for drug absorption and bioavailability.”

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