Computer-adjusted dosage of anticoagulant therapy improves the quality of anticoagulation

Abstract

Objective: Risks and benefits of anticoagulant therapy depend directly of the quality of anticoagulation. We performed a meta-analysis of published randomized trials to assess the overall effectiveness of computer-based prescription systems on the quality of anticoagulation.

Design: Randomized controlled trials were identified through electronic searches of the Medline database (1966-1997) and systematic analyses of the references of articles. Two investigators selected relevant papers and summarized data from the studies.

Methods: The outcome variable was the proportion of days within the target range of anticoagulation. A pooled estimate of the common odds ratio of being in the target range and its confidence interval was obtained by the Mantel-Haenszel method.

Results: Seven trials having included 1217 patients were identified. Computer systems were based on a pharmacokinetic-pharmacodynamic model and a bayesian prediction method. Most of them concerned the oral anticoagulant warfarin. The global odds ratio of being in the target range was 1.58 [95% CI: 1.34-1.86], thus meaning that the use of a computer for anticoagulation optimization increased by 58% the proportion of visits where patients were appropriately treated. The proportion of clinical events was too low for allowing a summary analysis.

Conclusion: Evidence from randomized controlled trials supports the effectiveness of computer-aided anticoagulant prescription. Diffusion of these systems in ambulatory care could increase the benefit/risk ratio of anticoagulant treatment at a low cost.