Estimating the cost-effectiveness of quality-improving interventions in oral anticoagulation management within general practice.

Objectives: A clinical trial, "Belgian Improvement Study on Oral Anticoagulation Therapy (BISOAT)," significantly improved the quality after implementing four different quality-improving interventions in four randomly divided groups of general practitioners (GPs). The quality-improving interventions consisted of multifaceted education with or without feedback reports on their performance, international normalized ratio (INR) testing by the GP with a CoaguChek device or computer-assisted advice for adapting oral anticoagulation therapy. The quality improvement in INR control versus baseline was similar in the four groups. The aim of the current study was to calculate the cost-effectiveness and influencing factors of the four quality-improving interventions compared with usual care.

Methods: Activity-based costing techniques with questionnaires were used to determine the global costs per patient per month in the different intervention groups. Effectiveness data were obtained from the BISOAT study. Cost-effectiveness was expressed as cost per additional day within a 0.5 range from INR target.

Results: The one-time cost of multifaceted education was 49,997 euro for the whole study. Monthly continuous costs per intervention ranged between 37 euro and 54 euro per patient. Using the CoaguChek in combination with the multifaceted education was associated with net savings and quality improvement, hence dominated usual care. Sensitivity analyses showed improved cost-effectiveness with extended duration and with increased program size.

Conclusion: Implementation of the combination multifaceted education with the use of the CoaguChek is a cost-effective new organizational model of oral anticoagulation management in general practice.