[Hemorrhagic complications of anti-vitamin K]

Adverse events related to oral anticoagulants represent a major public health problem. Hemorrhagic episodes are the most frequent complications and can be life-threatening. A 10 month prospective survey on all cases treated with anti-vitamin K (AVK), and admitted to emergency room of CHU Grenoble, was conducted to identify the hemorrhagic adverse drug events (HADE). The evaluation support was a directive questionnaire and consisted of 3 parts: patient characteristics, patient's medicated treatment and the hemorrhagic event. 216 patients treated with AVK were identified and 68 of them presented a hemorrhagic adverse drug event. 60 patients older than 65 years out of 158, presented HADE (38%); versus 8 patients < or = 65 years out of 58 (RR = 2.75; p = 0.0007). Among the patients who have their INR > or = 5, 79% developed HADE versus 16% in the group who had their INR < 5 (< 0.0001). In the group of patients who had a change in drug therapy within the 7 days preceding their admission, 47% developed HADE versus 25% of patients whose treatment was not modified: Anti-microbial agents were the drug most frequently involved. The patient's knowledge of INR value and signs of excess AVK were significant. Concerning missed dose, 48 patients declared taking the missed dose with the next dose or when they remembered: 35% of them developed HADE (p = 0.49).