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Dan Med Bull. 2002 Aug;49(3):252-5.

The quality of routine oral anticoagulant therapy in a large geographical area. A survey of 310,300 inhabitants.

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Department of Medicine and Cardiology, Aarhus County Hospital, Aarhus University Hospital, Denmark.



To identify all patients undergoing routine oral anticoagulant therapy (OAT) in a large geographic area as well as the quality of OAT.


In the admission area of Aarhus County Hospital, Denmark (310,300 inhabitants), we conducted a population-based prospective observational study 1 April 1997 to 31 March 1998, using the Laboratory Information System to identify all patients and their related International Normalized Ratio (INR)-values as well as their monitoring physician. Main outcome measures were, incidence rate, point prevalence and the quality of OAT based on measurement of the time (in days) of INR-values within therapeutic interval (TI) of OAT.


1609 patients (median age: 68.0 years; range 0.2-95.0) corresponding to 1155 patient-years on OAT were identified. 585 patients were started on OAT within the time period, corresponding to an incidence rate of 188 patients/year/100,000 inhabitants. September 1st 1997, 1174 patients were on OAT, equal to a point prevalence of 378 patients/year/100,000 inhabitants. Overall, 71% of treatment time (in days) INR was within the TI. Among patients monitored by an outpatient clinic or by a general practitioner, the time of INR within TI were 76.5% and 69.9%, respectively (p < 0.0001).


The result indicates that the quality of routine OAT in this geographical area is in accordance with other similar studies. The quality might be better in the outpatient clinics although the result could be due to selection bias. The method to identify OAT patients is convenient and precise, making continuous surveillance of rate of incidence, point prevalence as well as quality of OAT in large geographic areas, possible.

[Indexed for MEDLINE]

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