OBJECTIVES: To determine the effect of anti-factor Xa assay dosing of low-molecular-weight heparin (LMWH) on rates of venous thromboembolism (VTE), deep vein thrombosis (DVT), pulmonary embolism (PE), bleeding, and mortality among orthopaedic trauma patients.
DATA SOURCES: PubMed/MEDLINE, Embase, Ovid, Cochrane Central Register of Controlled Trials (CENTRAL), clinicaltrials.gov , and Scopus were systematically searched from inception of the database to 2021.
STUDY SELECTION: Prospective, retrospective, and randomized controlled trial studies were included if they compared rates of VTE, DVT, PE, bleeding, and/or mortality between orthopaedic trauma patients receiving anti-factor Xa-based LMWH dosing and those receiving standard dosing.
DATA EXTRACTION: Two independent reviewers screened titles and abstracts for eligibility. Study characteristics including study design, inclusion criteria, and intervention were extracted.
DATA SYNTHESIS: Meta-analysis was performed using pooled proportion of events (effect size) with 95% confidence intervals. A random-effects model was used. Heterogeneity was quantified by Higgins I 2 . Heterogeneity and variability between subgroups indicated differences in the pooled estimate represented by a P -value.
RESULTS: Six hundred eighty-five studies were identified, and 10 studies including 2870 patients were included. In total, 30.3% and 69.7% received an adjusted and nonadjusted dose of LMWH, respectively. The rate of VTE and DVT were significantly lower in the anti-factor Xa-adjusted cohort, whereas there was no statistically significant difference in rates of PE, bleeding, or mortality between the cohorts.
CONCLUSIONS: This systematic review and meta-analysis demonstrates that anti-factor Xa activity assay dosing of LMWH among orthopaedic trauma patients leads to a reduction in overall DVT rates, although not PE rates, without an increased risk of bleeding events.
LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
The only study (out of 10) that had an RCT design did not show any difference. The benefit of monitoring with anti-Xa (or TEG) to reduce DVT is thus based on studies with a high risk of bias.