Enoxaparin thromboprophylaxis in hospitalized obese pediatric patients.

Abstract

Enoxaparin is an anticoagulant used for pharmacologic thromboprophylaxis in pediatrics. Enoxaparin pharmacokinetics can be altered in the setting of obesity. Optimal enoxaparin dosing for thromboprophylaxis in children with obesity remains unclear. A retrospective review was conducted of pediatric patients who weighed ≥60kg with BMI≥95th percentile, received enoxaparin for thromboprophylaxis, and had at least one appropriately drawn anti-factor Xa(anti-Xa) from 2013 to 2022. Anti-Xa levels were reviewed for patients initially treated with enoxaparin 30mg every 12h. The average daily enoxaparin dose required to achieve an anti-Xa of 0.2-0.4 unit/mL, which was stratified by BMI percentile and weight, was calculated. Of 116 patients (median age 15.8 years) included for analysis, 106 patients were initially treated with enoxaparin 30mg every 12h. Anti-Xa levels were<0.2 unit/mL in 53% of patients with BMI>99th percentile and 54% of patients>100kg. Ninety-one patients had at least one anti-Xa 0.2-0.4unit/mL with an average daily enoxaparin dosing of 66mg. When stratified by severity of obesity, higher doses were required to attain an anti-Xa 0.2-0.4 unit/mL in patients with BMI>99th percentile compared with those with 95th-99th percentile (67.8±15.7 vs. 62±5.6mg/day, p=.01). Patients>100kg required significantly higher dose than those ≤100kg (69.1±15.5 vs 61.2±7.3mg/day, p=.002). Increased initial dosing and/or anti-Xa level monitoring should be considered in adolescents with severe obesity receiving enoxaparin thromboprophylaxis.