Aspirin in prevention of venous thromboembolism following hip fracture surgery: A systematic review and meta-analysis

Background: Many orthopaedic surgeons routinely prescribe aspirin (ASA) as prophylaxis for venous thromboembolism (VTE) following hip fracture surgery (HFS). The purpose of this study is to assess the effectiveness of aspirin to other agents in preventing VTE and mortality following hip fracture surgery. Methods: Following PRISMA guidelines, we performed a search for HFS studies from 1998 to 2023 reporting comparisons between aspirin and other chemoprophylaxis methods for VTE (DVT – deep vein thrombosis; PE – pulmonary embolism). SPSS Meta-analysis function was used to calculate Mean Effect Size Estimate (MESE) and 95 % Confidence Intervals for each outcome. Reverse Fragility Index (RFI) and Fragility Quotient (FQ) were calculated for each study. Results: Of the 847 articles screened, 4 studies with 5 comparisons met the search criteria to be included for analysis. A total of 1194 participants were included in these studies. There was a decreased risk of mortality seen with use of aspirin compared to other agents (MESE = 0.86, 95 % CI: [0.07–1.66]; p=.03). There was no increased risk of DVT or PE with use of aspirin (both p>.4). The overall RFI and FQ for all 19 outcomes were 12 (IQR: 6.5–15) and 0.080 (IQR: 0.027–0.110), respectively. Ten studies (52.6 %) reported a loss-to-follow-up (LTF) greater than the overall RFI. Conclusions: Aspirin demonstrates similar protective effects on prevention of VTE compared to other agents and may have significant protective effects on overall mortality following surgical intervention for hip fractures. However, the current evidence concerning its use in this arena is less than robust, with more than half of the studied outcomes considered statistically fragile.