[Comparative study of the stability of oral anticoagulant treatments (warfarin vs acenocoumarol)].

PURPOSE

To compare the stability of the effect of two oral anticoagulants, one of them (acenocoumarol) with a short half life and the other one with a long half life (warfarin) in patients in the stable phase of treatment (at least 2 months with treatment before entering the study).

PATIENTS AND METHODS

During a year period (January-December 1993) a comparative study of two groups of 53 patients each was performed: group 1 patients were treated with warfarin and group 2 with acenocoumarol. Both groups were paired with respect to age, sex, diagnosis for anticoagulant therapy and desired therapeutic range (INR 3-4.5). The mean value of controls per patient, the dosage changes, the evolutive controls and the incidence of haemorrhagic and thromboembolic episodes were studied.

RESULTS

The controls performed in group 1 were 728 in total with a mean value of 13.74 per patient and 800 in group 2 with a mean value of 15.09 per patient. A change in the dosage was performed in 214 controls in patients of group 1 and in 269 of group 2. Seventeen patients had 38 haemorrhagic episodes (2 major and 36 minor) in group 1, and 6 of group 2 had 20 episodes (2 major and 18 minor). Significant differences were observed in the mean value of controls (p = 0.04), the evolutive controls (p < 0.001), the global incidence of haemorrhages (p = 0.008) and incidence of minor ones (p = 0.006). No significant differences in dosage were observed. In both groups no thromboembolic episodes during the period of study were reported.

CONCLUSIONS

Anticoagulant treatment with warfarin is more stable than with acenocoumarol. The total controls and the mean value of controls per patient are decreased. Nevertheless with warfarin we have observed a greater incidence of haemorrhagic episodes.