Costs and effectiveness of using coumarins before, during and after coronary angioplasty.

BACKGROUND

In the Balloon Angioplasty and Anticoagulation Study (BAAS), coumarins added to routine aspirin therapy before coronary angioplasty reduced cardiac events at the cost of a slightly higher risk of bleeding complications.

OBJECTIVE

To determine the cost effectiveness of coumarin treatment, based on the occurrence of both cardiac and bleeding events.

METHODS

Effectiveness was measured, applying two definitions, in terms of the number of events occurring at one year. In the first definition, the occurrence of death, myocardial infarction (MI), or stroke was assessed. The second definition also included revascularisations and major bleeding episodes as an event. Costs were limited to direct medical costs. Cost effectiveness was addressed by probability ellipses representing the point estimates and uncertainties surrounding both costs and effectiveness.

RESULTS

At 1 year, death, MI or stroke occurred 1.1% less often when treating with aspirin plus coumarins rather than aspirin therapy alone. When revascularisations and major bleeding events were also included, the difference was 5.0%. Overall, the additional costs in relation to coumarin treatment were compensated by a reduction in repeat interventions. When including all costs, the savings associated with coumarin treatment were estimated at Euros 235 per patient after 1 year. The probability that coumarins are cost saving was estimated at 0.85. The probability that coumarins combine additional effectiveness with cost savings was estimated at 0.70 when survival free of MI or stroke as an effectiveness measure was considered, and at 0.83 when survival free of MI, stroke, revascularisation or major bleeding was considered.

CONCLUSIONS

Coumarin therapy added to routine aspirin therapy before coronary angioplasty, and continued during follow-up, may not only be considered more effective but also cost saving relative to aspirin therapy alone.