Anticoagulants versus non-steroidal anti-inflammatories or placebo for treatment of venous thromboembolism.

BACKGROUND: Venous thromboembolism (VTE) is the term given to any thromboembolic event (blocking of a blood vessel by a blood clot) occurring in the venous system. The current treatment recommended for VTE is anticoagulation (reduction of the blood's ability to clot). The aim of this review is to summarize results from randomized controlled trials (RCTs) for the effectiveness of anticoagulants (heparins, including low molecular weight heparins and vitamin K antagonists) in the treatment of VTE, compared to non-steroidal anti-inflammatory drugs (NSAIDs) or placebo.

OBJECTIVES: To examine the randomized controlled evidence for the effectiveness and safety of anticoagulant treatment compared to NSAIDs or placebo in patients with VTE on the incidence of fatal and non-fatal pulmonary emboli (PE) and the recurrence or extension of deep vein thrombosis (DVT).

SEARCH STRATEGY: The Cochrane Peripheral Vascular Diseases (PVD) Group searched their Specialized Trials Register (last searched 26 July 2005) and the Cochrane Central Register of Controlled Trials (CENTRAL) database (last searched Issue 3, 2005). In addition, DKC also searched reference lists and contacted pharmaceutical companies and experts in the field.

SELECTION CRITERIA: All randomized trials of anticoagulants versus NSAIDs or placebo in the initial treatment of VTE (DVT or PE or both).

DATA COLLECTION AND ANALYSIS: DKC and JM independently assessed trial quality and extracted data. JCP (biostatistician) analyzed the design elements and feasibility of a future randomized controlled trial to determine definitively efficacy and safety of anticoagulants in VTE treatment.

MAIN RESULTS: Two RCTs were included. Data were not pooled because of heterogeneity between the studies. The two RCTs were too small to determine any difference in mortality, occurrence of pulmonary emboli, progression or return of DVT between patients treated with anticoagulation and those receiving no anticoagulation.

AUTHORS' CONCLUSIONS: The limited evidence from RCTs of anticoagulants versus NSAIDs or placebo is inconclusive regarding the efficacy and safety of anticoagulants in VTE treatment. The use of anticoagulants is widely accepted in clinical practice, so a further RCT comparing anticoagulants to placebo could not ethically be carried out.