Aspirin for prophylaxis of VTE in patients with Hip/ Knee replacement: Systematic review and Meta-analysis of Non-Randomized studies

Aspirin as an agent for thromboprophylaxis in patients with total knee replacement (TKR) and total hip replacement (THR) is gaining a lot of importance owing to its efficacy and safety in preventing venous thromboembolism (VTE) complications. The current guidelines do not recommend aspirin over other anticoagulants as the data from the meta-analysis of randomized controlled trails (RCTs) lacked a significant sample to draw conclusive results. The present study was aimed to carry out a systematic review and meta-analysis of nonrandomized studies (NRSs) to determine the effect of aspirin as prophylaxis for VTE. A complete electronic search was conducted at PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar for relevant articles published till March 2021. Any postsurgical VTE event (deep vein thrombosis and/or pulmonary embolism) is considered the primary outcome and adverse events as secondary outcomes. Both efficacy and safety outcomes were reported as pooled risk estimates with 95% confidence interval (CI) with a level of significance at P < 0.05. A total of 21 studies were identified for the analysis. The overall risk of occurrence of VTE among the patients taking aspirin was not significantly different from anticoagulants (risk ratio [RR]: 0.78, 95% CI: 0.52-1.15). Patients who underwent THR had a higher risk for VTE with aspirin (RR: 1.50, 95% CI: 1.35-1.61), whereas the patients who underwent TKR showed a lower risk of VTE with aspirin (RR: 0.80, 95% CI: 0.75-0.85). Meta-analysis of NRS advocates the role of aspirin as a prophylactic agent for VTE, especially for patients who are in need for TKR. Further RCTs are required to reestablish the role of aspirin, especially in patients undergoing THR.