Enoxaparin Versus Tinzaparin for Venous Thromboembolic Prophylaxis During Rehabilitation After Acute Spinal Cord Injury: A Retrospective Cohort Study Comparing Safety and Efficacy

Objective To compare the safety and efficacy of 3 low-molecular-weight heparin (LMWH) treatments (enoxaparin, 40 mg once daily, with an alternative LMWH, tinzaparin, 3500 or 4500 units once daily) for the prevention of venous thromboembolic events (VTEs) after acute spinal cord injury (SCI). Design Retrospective, chart review study. Setting Acute inpatient rehabilitation facility. Participants Patients admitted to acute rehabilitation within 3 months of either a traumatic or nontraumatic SCI during a 15-month time frame and who received either enoxaparin or tinzaparin for VTE prophylaxis. Main outcome measures Symptomatic VTE incidence and bleeding events during acute rehabilitation. Results A total of 140 participants who met inclusion criteria were admitted at a median of 15 days after an acute SCI. Before admission to rehabilitation, 23.6% were not on any VTE prophylaxis, 55.7% were on enoxaparin, 17.1% were on unfractionated heparin, 1.4% were on treatment doses of a LMWH, and 2.1% did not have documentation available regarding type of prophylaxis before admission. No patients were receiving tinzaparin before admission. During rehabilitation, 68 participants received prophylaxis with enoxaparin, whereas 14 and 58 participants received tinzaparin 3500 or 4500 units, respectively. Symptomatic VTE developed in 14 patients during rehabilitation, including 4 developing pulmonary emboli. Compared with patients receiving tinzaparin 3500 units, both those receiving enoxaparin had significantly reduced odds of VTE (odds ratio [OR] 0.12; 95% confidence interval [95% CI] 0.02-0.65)] and those receiving tinzaparin 4500 units had significantly reduced odds of VTE (OR 0.18; 95% CI 0.03-0.93). After we adjusted for age, previous pharmacologic prophylaxis, and etiology for the SCI (traumatic vs nontraumatic) via propensity scores, pharmacologic prophylaxis with enoxaparin remained protective for VTE compared with tinzaparin 3500 units (adjusted OR 0.15; 95% CI 0.02-0.93). The use of prophylaxis before admission with enoxaparin compared with no prophylaxis was associated with decreased risk of VTE during rehabilitation (adjusted OR 0.20; 95% CI 0.04-0.88); however, this association was no longer significant when we adjusted for prophylaxis during rehabilitation. The etiology for the SCI and the presence of an inferior vena cava filter were not associated with VTE. One patient receiving enoxaparin required transfer for a bleeding event, and no patients had greater than a 1-g decrease in hemoglobin during the rehabilitation stay. Conclusions VTE was more prevalent in participants receiving tinzaparin 3500 units than in participants who received tinzaparin 4500 units or enoxaparin. Bleeding events were low with the use of LMWH for prophylaxis during acute rehabilitation. Although the use of prophylaxis before rehabilitation may be protective of VTE events, after we adjusted for VTE prophylaxis during rehabilitation, type of previous prophylaxis was not found to be significantly protective of VTE events during rehabilitation.