[Prospective study of oral anticoagulation control in 110 very elderly hospitalized patients and of risk factors for poor control].
OBJECTIVE
The primary aim of this study was to analyze the quality of oral anticoagulation management in the real-life practice of hospital geriatric departments, in the absence of a formal dose-adjustment protocol. The secondary objective was to identify factors associated with international normalized ratios (INR) outside the target range.


METHODS
This prospective study was conducted between November 2004 and August 2005 in our hospital's acute geriatric care and geriatric rehabilitation units. It included 110 subjects older than 65 years, all taking fluindione (target INR range of 2 to 3). Indications for oral anticoagulation were atrial fibrillation, venous thromboembolism, and pulmonary embolism. Patients were eligible for inclusion if they had at least 4 INR measurements, and we assessed a maximum of 20 such measures per patient.


RESULTS
The study included 74 patients in the acute geriatric unit and 36 subjects in rehabilitation units (mean age: 85 years [65-97 years]), who had 1079 INR tests during the study period (mean per patient: 9.8 (+/-5.5)). Overall, 333 patients (31%) were in the target range of 2-3, 48% below 2, 21% above 3, and 3.6% above 5. The time interval between INR tests did not vary when INR was below 2, but we noted a nonsignificant trend towards a reduction in the average testing interval when INR was above 3 (p=0.079). No bleeding or thrombotic complications were reported during the study. Of the 11 predefined variables, only cancer (history or current) was significantly associated with elevated INR.


CONCLUSIONS
This study confirms the difficulty of controlling INR in anticoagulation therapy of elderly subjects. Only 31% of tests showed INR in the target range of 2 to 3, a rate lower than in other cohorts. These results may be explained by the high rate of comorbidities in this very old study population.
Vogel
Thomas
T
Pôle de gériatrie, Hôpital de la Robertsau, Hôpitaux universitaires de Strasbourg, F-67091 Strasbourg Cedex, France. Thomas.vogel@chru-strasbourg.fr
Coriol
Virginie
V
Kaltenbach
Georges
G
Kiesmann
Michèle
M
Berthel
Marc
M
D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D008297:Male; D010630:Phenindione / Q000031:analogs & derivatives* / Q000627:therapeutic use; D011446:Prospective Studies; D012307:Risk Factors; D014812:Vitamin K / Q000037:antagonists & inhibitors*
D000925:Anticoagulants; D014812:Vitamin K; D010630:Phenindione; C017673:fluindione