Impact of thromboprophylaxis guidelines on clinical outcomes following total hip and total knee replacement

Background: The American College of Chest Physicians (ACCP) guidelines recommends thromboprophylaxis for total hip replacement (THR) and total knee replacement (TKR) patients. We examined alignment with ACCP thromboprophylaxis guidelines among THR/TKR patients, and compared symptomatic venous thromboembolism (VTE), bleeding event rates and risk factors for VTE between patients receiving ACCP-recommended thromboprophylaxis ('ACCP') and those who did not ('non-ACCP'). Methods: This retrospective observational study used a large US health plan claims database that was linked to an inpatient database containing detailed inpatient medication use and a database containing date-of-death information. Patients who had THR/TKR surgery between April 01, 2004 and December 31, 2006 were included. Comparisons of VTE and bleeding events between ACCP and non-ACCP patients were analyzed using chi-squared tests and multivariate logistic regression. Results: Of 3,497 linked patients, 1,395 (40%) received ACCP recommended thromboprophylaxis. Of the patients who received non-ACCP recommended prophylaxis the majority (81%) received shorter than the recommended minimum 10 day prophylaxis and 118 (5.6%) of patients received no prophylaxis. Overall, non-ACCP patients were almost twice as likely to experience an incident DVT (3.76% versus 2.01%, p = 0.003) and more than eight times as likely to experience an incident PE (1.19% versus 0.14%, p = 0.001) relative to ACCP patients; there were no statistically significant difference in bleeding rates. Multivariate logistic regression indicated that the odds of a VTE event were significantly lower for ACCP patients (DVT: OR = 0.54; p = 0.006; PE: OR = 0.12; p = 0.004). Conclusions: This study offers a unique perspective on 'real-world' thromboprophylaxis patterns and associated outcomes in THR and TKR patients in the US. It suggests that only 40% of THR/TKR patients receive ACCP-recommended thromboprophylaxis and that not receiving ACCP thromboprophylaxis is an independent risk factor for both DVT and PE.