[Extent and quality of anti-coagulation treatment with coumarin derivatives by the Dutch Thrombosis Services].

Objective: To obtain an impression of the extent and quality of the anti-coagulation treatment with coumarin derivatives carried out by the Thrombosis Services in the Netherlands.

Design: Descriptive.

Method: Data were drawn from the medical annual reports of 62 of the 63 Thrombosis Services in the Netherlands over the period 1998-2002. In 2002 the Thrombosis Services treated 325,072 patients and performed 4,469,730 INR laboratory tests. The half-yearly figures produced by the Thrombosis Services were calculated as an average percentage per year per thrombosis service and then recalculated as a percentage per year.

Results: Seventy-three per cent of the patients were treated for an arterial and 27% for a venous indication. Depending on the required intensity of anticoagulation a mean of 74-78% of the long-term treated patients fell within the therapeutic range and a mean of 6-10% below. The mean number of major bleedings per 100 treatment years was 1.0. A mean of 79% of the patients was treated with acenocoumarol and 21% with phenprocoumon. When acenocoumarol was used, a mean of 72-77% fell within the therapeutic range and in the case of phenprocoumon 79-82%. In the last few years the number of patients had increased due to a growing number of patients treated for atrial fibrillation. The percentages of INR within the therapeutic range were unchanged or showed a slight increase.

Conclusion: The quality of the anticoagulation therapy with coumarin derivatives was good or acceptable.