title: The effect of aspirin and low-molecular-weight heparin on venous thromboembolism after hip replacement: a non-randomised comparison from information in the National Joint Registry.
abstract: We compared thromboembolic events, major haemorrhage and death after total hip replacement in patients receiving either aspirin or low-molecular-weight heparin (LMWH). We analysed data from the National Joint Registry for England and Wales linked to an administrative database of hospital admissions in the English National Health Service. A total of 108,584 patients operated on between April 2003 and September 2008 were included and followed up for 90 days. Multivariable risk modelling and propensity score matching were used to estimate odds ratios (OR) adjusted for baseline risk factors. An OR < 1 indicates that rates are lower with LMWH than with aspirin. In all, 21.1% of patients were prescribed aspirin and 78.9% LMWH. Without adjustment, we found no statistically significant differences. The rate of pulmonary embolism was 0.68% in both groups and 90-day mortality was 0.65% with aspirin and 0.61% with LMWH (OR 0.93; 95% CI 0.77 to 1.11). With risk adjustment, the difference in mortality increased (OR 0.84; 95% CI 0.69 to 1.01). With propensity score matching the mortality difference increased even further to 0.65% with aspirin and 0.51% with LMWH (OR 0.77; 95% CI 0.61 to 0.98). These results should be considered when the conflicting recommendations of existing guidelines for thromboprophylaxis after hip replacement are being addressed.
authors: South Tees Hospitals Foundation Trust, James Cook Hospital, Marton Road, Middlesbrough TS4 3BW, UK.
authors: S S
authors: SS
authors: Jameson
authors: S C
authors: SC
authors: Charman
authors: P J
authors: PJ
authors: Gregg
authors: M R
authors: MR
authors: Reed
authors: J H
authors: JH
authors: van der Meulen
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D001241:Aspirin / Q000009:adverse effects / Q000627:therapeutic use*; D004341:Drug Evaluation / Q000379:methods; D004739:England / Q000453:epidemiology; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D019106:Postoperative Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D011655:Pulmonary Embolism / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D014852:Wales / Q000453:epidemiology
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D001241:Aspirin