The magnitude of an iatrogenic disorder:A systematic review of the incidence of venous thromboembolism for general medical inpatients

Summary

Venous thromboembolism (VTE) is recognized as a potential serious complication of hospitalization, and anticoagulant prophylaxis is widely recommended for medical inpatients.The purpose of this review was to systematically inspect the literature to determine the incidence of VTE without anticoagulant prophylaxis for hospitalized general medical patients. A systematic review was performed using MEDLINE and Cochrane Collaboration searches of the English-language literature. References of the retrieved articles were reviewed for additional studies, and pharmaceutical companies were contacted directly to identify unpublished studies. Studies were eligible if they reported the incidence of symptomatic or asymptomatic VTE in hospitalized general medical patients and included a group which did not receive prophylaxis. Eight trials were identified. Study design, quality, and results were heterogeneous.The incidence of symptomatic VTE without prophylaxis was examined in three trials; the incidence was 2.3% in the only randomized trial, and was 0.8% and 6.2% in two observational studies. The incidence of asymptomatic VTE ranged from 3.7% to 26.0% (median 12.8%). Risk factors identified were older age, prior VTE, and obesity. Though there is little high quality evidence, the best estimate of the incidence of hospital-acquired VTE for general medical patients is approximately 2% for patients at moderate to high risk and <1% for patients at low risk. Further studies are needed to more precisely define a low risk group for whom anticoagulant prophylaxis is unnecessary.

Keywords

Venous thromboembolism - anticoagulation - prophylaxis - deep vein thrombosis - pulmonary embolism

Footnote: This study was presented at the national meeting of the Society of General Internal Medicine, New Orleans, Louisianna, USA in May 2005.

• References

• 1 Geerts WH, Pineo GF, Heit JA. et al. Prevention of venous thromboembolism. Chest 2004; 126: 338S-400S.
• 2 Losito R, Gattiker H, Bilodeau G. et al. Levels of antithrombin III, α2-macroglobulin, and α1-antitrypsin in acute ischemic heart disease. J Lab Clin Med 1981; 97: 241-50.
• 3 Gardlund B. Randomized controlled trial of lowdose heparin for prevention of fatal PE in patients with infectious diseases. Lancet 1996; 347: 1357-61.
• 4 Samama MM, Cohen AT, Darmon JV. et al. A comparison of enoxaparin with placebo for the prevention of venous thromboembolism in acutely ill medical patients. NEJM 1999; 341: 793-800.
• 5 Belch J, Lowe DO, Ward AG. et al. Prevention of deep vein thrombosis in medical patients by low-dose heparin. Scott Med J 1981; 26: 115-7.
• 6 Thromboembolism Risk Factors Consensus Group (THRIFT). Risk of and prophylaxis for venous thromboembolism in hospital patients. BMJ 1992; 305: 67-74.
• 7 Warkentin TE, Greinacher A. Heparin-induced thrombocytopenia: recognition, treatment, and prevention. Chest 2004; 126: 311S-337S.
• 8 Moher D, Schulz KF, Altman DG. et al. The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials. Lancet 2001; 357: 1191-4.
• 9 Leizorovicz A, Cohen A, Turpie A. et al. Randomized, placebo-controlled trial of dalteparin for the prevention of venous thromboembolism in acutely ill medical patients. Circulation 2004; 110: 874-9.
• 10 Kierkegaard A, Norgren L, Olsson CG. et al. Incidence of deep vein thrombosis in bedridden non-surgical patients. Acta Med Scand 1987; 222: 409-14.
• 11 Dhôte R, Pellicer-Coeuret M, Belouet-Moreau C. et al. Venous thromboembolism in medical inpatients: prophylaxis with low weight heparin in a university hospital and prevalence of thromboembolic events. Clin Appl Throm Haem 2001; 07: 16-20.
• 12 Cohen AT, Davidson BL, Gallus AS. et al. Fondaparinux for the prevention of venous thromboembolism in acutely ill medical patients. Blood. 2003 102. Abstract 42.
• 13 McGarry LJ, Thompson D. Retrospective database analysis of the prevention of venous thromboembolism with low-molecular-weight heparin in acutely ill medial inpatients in community practice. Clin Ther 2004; 26: 419-30.