[Excess antivitamin K in elderly hospitalised patients aged over 70. A one-year prospective survey].
BACKGROUND
Antivitamin K treatments (AVK) are related to increased morbidity and mortality, notably in elderly patients. The International Normalized Ratio (INR) should be well controlled and its stabilisation within the therapeutic range help to prevent the haemorrhagic complications.


METHODS
A one-year prospective survey on all the cases of excess AVK was conducted in hospitalised patients aged over 70.


RESULTS
During the study period, 225 hospitalised patients treated with AVK (mean age 84 years) were identified: 62% received warfarin, 19% fluindione, 8% acenocoumarol and 11% received several successive AVK. During this period, 1.904 INR measurements were recorded: 97 (5.1%) were > or =5.0 and 12 (0.63%) were > or =9.0. In all, 59 patients (23.1%) exhibited one or several episodes of excess AVK (INR > or =5.0) and 57 exhibited a target INR of 2.5. Three patients died of accidental haemorrhage--two of them due to intra-cerebral bleeding--among the 59 patients with excess AVK. In three cases, the INR was greater than 7.0 at the time of the accident.


CONCLUSIONS
In half of the cases of excess, the episode occurred during the month following initiation of treatment with AVK. In nearly two thirds of cases, a change had been made in drug therapy in the 10 days preceding the excess, with the prescription of a drug enhancing the effect of the AVK: anti-infection agents (antibiotics and anti-fungals) and amiodarone were the drugs most frequently involved. Oral or intravenous vitamin K1 was administered in only 19% of cases.


CONCLUSIONS
In very old patients treated with oral anticoagulants, certain risk factors must be identified: the initiation period of treatment, the occurrence of an intercurrent disease and the subsequent change in the drug therapy. INR monitoring should be intensified in order to detect any excess and, if detected, ensure the optimal management of the patient.
Siguret
V
V
Laboratoire d'hématologie, G.H. Charles Foix-Jean Rostand (AP-HP), Ivry-sur-Seine (94).
Esquirol
C
C
Debray
M
M
Gouin
I
I
Andreux
J-P
JP
Pautas
E
E
D015110:4-Hydroxycoumarins; D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000494:pharmacology; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects* / Q000378:metabolism; D000935:Antifungal Agents / Q000494:pharmacology; D003128:Coma / Q000139:chemically induced; D004334:Drug Administration Schedule; D062787:Drug Overdose; D004357:Drug Synergism; D005260:Female; D006408:Hematoma, Subdural / Q000139:chemically induced; D006470:Hemorrhage / Q000139:chemically induced; D006760:Hospitalization; D006801:Humans; D007192:Indenes; D019934:International Normalized Ratio / Q000379:methods; D008297:Male; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000139:chemically induced; D013921:Thrombocytopenia / Q000139:chemically induced; D014812:Vitamin K / Q000037:antagonists & inhibitors; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects* / Q000378:metabolism
D015110:4-Hydroxycoumarins; D000889:Anti-Arrhythmia Agents; D000900:Anti-Bacterial Agents; D000925:Anticoagulants; D000935:Antifungal Agents; D007192:Indenes; C011664:antivitamins K; D014812:Vitamin K; D014859:Warfarin; D000638:Amiodarone