Article type
Year
Abstract
Background: The efficacy of long-term oral anticoagulation for the prevention of vascular events has been established by several studies, but this benefit could be offset by fatal adverse events. Since the previous studies have focused on specific clinical settings, it is necessary to examine the overall efficacy and safety in a wide range of high risk patients.
Objectives: The objective of this review is to assess global efficacy and safety of long term anticoagulation for preventing vascular events, and to compare its efficacy and safety among different clinical settings.
Methods: The Cochran Central Register of Controlled trials register(The Cochrane Library issue 4 2003), MEDLINE(January 1966 to November 2003), EMBASE (January 1974 to November 2003) and reference lists of published articles have been searched. In addition, a hand search from individual reports, review articles, references in meta-analysis, and consensus statements has been performed. All randomized controlled trials designed to compare INR (International Normalized Ratio) adjusted long-term (for one or more years) oral anticoagulation with placebo, antiplatelets, or low molecular weight heparin as either a primary or a secondary prevention for death or non-fatal vascular events were included in this review. Global efficacy and safety of oral anticoagulation have assessed with the following different clinical settings; atrial fibrillation (Af) , high risk of ischemic heart disease without the previous history of vascular events (HR), stroke or TIA(CVD), ischemic heart disease(IHD), and high risk of venous thromboembolism(VTE). Global efficacy was defined as a prevention of any cause of death, nonfatal stroke, nonfatal myocardial infarction or nonfatal venous thromboembolism. Safety outcome was; global efficacy was defined assessed using three categories; 1) a major bleeding which includes intracranial bleeding or clinical events that required blood transfusion, 2) an intracranial hemorrhage, and 3) an extracranial hemorrhage.) Two reviewers independently extracted data and assessed trial quality. The methodological quality of each trial was assessed using a Jadad scale.
Results: Twenty-two trials were found to be eligible. Among them, seven trials were in, one trial was in HR, IHD, six trials in CVD and three trials in VTE. Anticoagulation significantly increased an overall efficacy comparing to that of control group, whose odds ratio(95% confidence interval) is 0.67(0.55 to 0.81). For different clinical settings, odds ratio of global efficacy was 0.51 (0.32-0.82) in AF, 0.63(0.52-0.76) in HR, 0.95(0.65-1.38) in CVD, 0.39 (0.15-1.00) in VTE, respectively. Anticoagulation, however, significantly reduced its safety with odds ratio, 2.57(1.76 to 3.76). It was similar among different clinical settings. Extracranial hemorrhage and intracranial hemorrhage were also increased in all clinical settings (odds ratios are 2.58 (1.69-3.53) and 3.14(1.93-5.12), respectively).
Conclusions: A significant overall efficacy of long-term oral anticoagulation for preventing vascular events has been found, however, its safety has also reduced. Moreover, it varied according to different clinical settings.
Objectives: The objective of this review is to assess global efficacy and safety of long term anticoagulation for preventing vascular events, and to compare its efficacy and safety among different clinical settings.
Methods: The Cochran Central Register of Controlled trials register(The Cochrane Library issue 4 2003), MEDLINE(January 1966 to November 2003), EMBASE (January 1974 to November 2003) and reference lists of published articles have been searched. In addition, a hand search from individual reports, review articles, references in meta-analysis, and consensus statements has been performed. All randomized controlled trials designed to compare INR (International Normalized Ratio) adjusted long-term (for one or more years) oral anticoagulation with placebo, antiplatelets, or low molecular weight heparin as either a primary or a secondary prevention for death or non-fatal vascular events were included in this review. Global efficacy and safety of oral anticoagulation have assessed with the following different clinical settings; atrial fibrillation (Af) , high risk of ischemic heart disease without the previous history of vascular events (HR), stroke or TIA(CVD), ischemic heart disease(IHD), and high risk of venous thromboembolism(VTE). Global efficacy was defined as a prevention of any cause of death, nonfatal stroke, nonfatal myocardial infarction or nonfatal venous thromboembolism. Safety outcome was; global efficacy was defined assessed using three categories; 1) a major bleeding which includes intracranial bleeding or clinical events that required blood transfusion, 2) an intracranial hemorrhage, and 3) an extracranial hemorrhage.) Two reviewers independently extracted data and assessed trial quality. The methodological quality of each trial was assessed using a Jadad scale.
Results: Twenty-two trials were found to be eligible. Among them, seven trials were in, one trial was in HR, IHD, six trials in CVD and three trials in VTE. Anticoagulation significantly increased an overall efficacy comparing to that of control group, whose odds ratio(95% confidence interval) is 0.67(0.55 to 0.81). For different clinical settings, odds ratio of global efficacy was 0.51 (0.32-0.82) in AF, 0.63(0.52-0.76) in HR, 0.95(0.65-1.38) in CVD, 0.39 (0.15-1.00) in VTE, respectively. Anticoagulation, however, significantly reduced its safety with odds ratio, 2.57(1.76 to 3.76). It was similar among different clinical settings. Extracranial hemorrhage and intracranial hemorrhage were also increased in all clinical settings (odds ratios are 2.58 (1.69-3.53) and 3.14(1.93-5.12), respectively).
Conclusions: A significant overall efficacy of long-term oral anticoagulation for preventing vascular events has been found, however, its safety has also reduced. Moreover, it varied according to different clinical settings.