Assessment of bleeding events associated with short-duration therapeutic enoxaparin use in the morbidly obese.

BACKGROUND

Enoxaparin dosing for patients with morbid obesity is uncertain, and therefore, an elevated incidence of bleeding may exist in this group.

OBJECTIVE

To determine if increased bleeding events occur in patients with morbid obesity (body mass index ≥ 40 kg/m(2)) compared with lower-weight patients with treatment doses of enoxaparin.

METHODS

Patients at a single, academic medical center receiving enoxaparin for at least 24 hours from July to December 2009 were retrospectively evaluated. Patients with morbid obesity were randomly selected among the total cohort and were matched with lower-weight controls (1:2 ratio) based on the presence of renal dysfunction (serum creatinine >1.4 mg/dL). Bleeding events, defined on the basis of laboratory changes, administration of blood products, or clinical data, occurring up to 24 hours after enoxaparin administration were evaluated. Independent risk factors for bleeding were assessed via multivariate analysis.

RESULTS

The maximum single dose administered throughout the study was 150 mg, and the largest patient enrolled weighed 175 kg. Final enoxaparin doses in morbidly obese (0.98 mg/kg) patients were lower compared with that in controls (1.04 mg/kg, P < .01). The proportion of patients with bleeding events was 29% in the morbidly obese and 23.5% in the control group (P = .30). Enoxaparin doses <0.9 mg/kg (adjusted odds ratio [AOR] = 2.35; 95% CI = 1.01-5.47; P = .04), durations of therapy beyond 48 hours (AOR = 2.42; 95% CI = 1.35-4.33; P < .01), and female gender (AOR = 2.05; 95% CI = 1.12-3.73; P = .02) were associated with bleeding, whereas warfarin use (AOR = 0.46; 95% CI = 0.26-0.81; P < .01) was associated with fewer bleeding events.

CONCLUSIONS

Results suggest that dosing enoxaparin in morbidly obese patients (up to 175 kg in weight) with doses capped at 150 mg was not associated with increased bleeding incidence.