Enoxaparin for VTE thromboprophylaxis during inpatient rehabilitation care: assessment of the standard fixed dosing regimen

Background: We aimed to examine the efficiency of fixed daily dose enoxaparin (40 mg) thromboprophylaxis strategy for patients undergoing inpatient rehabilitation. Methods: This was an observational, prospective, cohort study that included 63 hospitalized patients undergoing rehabilitative treatment following sub-acute ischemic stroke (SAIS) or spinal cord injury (SCI), with an indication for thromboprophylaxis. Anti-Xa level measured three hours post-drug administration (following three consecutive days of enoxaparin treatment or more) was utilised to assess in vivo enoxaparin activity. An anti-Xa level between 0.2-0.5 U/ml was considered evidence of effective antithrombotic activity. Results: We found sub-prophylactic levels of anti-Xa (<0.2 U/ml) in 19% (12/63). Results were within the recommended prophylactic range (0.2-0.5 U/ml) in 73% (46/63) and were supra-prophylactic (>0.5 U/ml) in 7.9% (5/63) of patients. Anti-Xa levels were found to inversely correlate with patients’ weight and renal function as defined by creatinine clearance (CrCl) (p<0.05). Conclusions: Our study confirmed that a one-size-fits-all approach for venous thromboembolism (VTE) prophylaxis may be inadequate for rehabilitation patient populations. The efficacy of fixed-dose enoxaparin prophylaxis is limited and may be influenced by renal function and weight. This study suggests that anti-Xa studies and prophylactic enoxaparin dose adjustments should be considered in certain patients, such as those who are underweight, overweight and or have suboptimal renal function. Trial registration: No. NCT103593291, registered August 2018.