[Risk factors of serious bleeding among ambulatory patients taking antivitamin K aged 75 and over].

The benefits of anti-vitamin K (AVK) drugs have been acknowledged in several indications. Such indications increasing with increasing age, AVK prescriptions also increases with age. At the same time, conditions involving significant bleeding are common in this elderly population. It is thus essential to recognize the determining factors. This study included all patients taking AVK drugs aged 75 years and older who sought emergency care at the Cochin Hospital from January to December 2011 for significant bleeding. These patients were compared with a cohort of patients aged 75 years or older who were taking AVK drugs and who were admitted to the same unit during the same time period for other reasons. The case-control comparison included demographic data, comorbidity factors, multiple medications, emergency measured INR, and CHA2DS2VASC level. The hemorrhagic risk was evaluated by HEMORR2HAGES and HAS-BLED. A total of 34 patients were studied and compared with 70 case-controls. The Charlson comorbidity index was higher in patients than case-controls (P<0.05), with a much higher hemorrhagic risk for scores ≥ 9 (OR=2.5; P<0.05). Multiple medication was also more predominant in patients (P<0.05). The risk of serious hemorrhage was also higher when the hemorrhagic scores were high, especially for HEMORR2HAGES (P<0.0001) and HAS-BLED (P<0.001). The risk of serious hemorrhage in elderly outpatients taking AVK drugs is related to their higher comorbidity and hemorrhagic levels which need to be evaluated before starting or stopping AVK treatment.