Influence of Obesity on the Safety and Efficacy of Antithrombotic Therapy: A Systematic Review and Meta-Analysis

Obese individuals have been historically underrepresented in clinical trials. Considering their association with a higher risk of venous thromboembolism (VTE) and acute coronary syndrome (ACS), it is necessary to establish a more suitable anticoagulation regimen for this group of patients.

To evaluate the influence of obesity on the safety and efficacy of antithrombotic therapy in patients with ACS or VTE.

This is a systematic review and meta-analysis that used 5 main international databases. We selected clinical trials or observational studies that compared the occurrence of clinical outcomes (mortality or bleeding) between obese and non-obese patients using parenteral anticoagulants for the treatment of ACS or VTE. P value < 0.05 was used for all analyses.

Six articles, with a total of 40,939 patients, were eligible, being 3 randomized clinical trials and 3 retrospective cohorts. Of the patients, 87.7% had ACS. The incidence of major bleeding was similar between groups (relative risk [RR]: 0.90, 95% confidence interval [CI]: 0.77 to 1.04, p = 0.14). The outcome remained comparable when studies were analyzed separately by anticoagulant: enoxaparin (RR: 0.87, 95% CI, 0.70 to 1.08, p = 0.21) or unfractionated heparin (RR: 0.96, 95% CI, 0.79 to 1.17, p = 0.67). The mortality rate was measured in only 2 studies, both in ACS, and it was lower in obese patients (RR: 0.71, 95% CI 0.59 to 0.87, p = 0.0007).

In patients treated for VTE or ACS, rates of bleeding were comparable between obese and non-obese patients, regardless of the anticoagulant used. The lower mortality rate observed in obese patients may represent the effect of unaccounted confounding.