PB1323 - Venous thromboembolism in obese patients: a ten-year experience

Background: Obesity is an increasing global threat with known associations to venous thromboembolism (VTE). There is, however, a lack of consensus in the VTE management of obese patients, particularly in extremes of weight (>120kg).

Aims: To review the impact of obesity on VTE treatment and outcomes.

Methods: A retrospective analysis was conducted of VTE presentations (DVT +/- PE) to Northern Health, Victoria, Australia, from January 2011 to December 2020. Morbidly obese patients (defined as >120kg) were compared to those ≤120kg. Patients with malignancy and those without documented weight were excluded. The median follow-up was 55 months.

Results: 2362 VTE cases, including 194 patients with weight >120kg were identified (see Table 1). The morbidly obese patients were younger (median age 47 years) and more likely to have previous history of VTE (n=78, 40%). They were more likely to present with unprovoked VTE (59% vs 45%, p< 0.001) and major VTE (75% vs 67%, p=0.028) compared to those ≤120kg. Warfarin was the most common choice of anticoagulant in patients >120kg. The morbidly obese patients had the highest rates of VTE recurrence off anticoagulation (7.8/100-patient years; HR 2.0 (95% CI 1.3-3.0)) when comparing to patients ≤120kg. There were no differences in clinically significant bleeding rates.
A subanalysis of enoxaparin anti-Xa levels performed on patients >120kg (see Table 2) demonstrated no differences in the rate of therapeutic levels achieved using uncapped (1mg/kg twice daily) or reduced ( < 1mg/kg twice daily) strategies, with no differences in thrombosis or bleeding rates across strategies.

Conclusion(s): Morbid obesity is associated with increased clot burden and higher rate of VTE recurrence off anticoagulation without increased clinically significant bleeding. No differences were seen between uncapped or reduced enoxaparin dosing strategies in these patients. As the prevalence of global obesity rises, it is important to optimise the anticoagulation strategies in this population.