Monitoring of international normalized ratios: comparison of community nurses with family physicians

To determine whether community-based, nurse-led monitoring of the international normalized ratio (INR) in patients requiring long-term warfarin therapy was comparable to traditional physician monitoring.

A retrospective cohort analysis of patients taking long-term warfarin therapy.

The study used data gathered from 3 family medicine clinics in a primary care network in Edmonton, Alta.

Medical records of patients currently taking warfarin were examined.

Implementation of nurse-led monitoring in a primary care network in place of standard family physician INR monitoring.

The degree of INR control before and after the implementation of nurse-run INR monitoring was assessed. The average proportion of time spent outside of therapeutic INR ranges, as well as the average number of days between successive INR readings, was calculated and compared. The degree of control placed patients into either a good-control group (out of range ≤ 25% of the time) or a moderate-control group (out of range > 25% of the time) and these groups were compared.

Before nurse monitoring, INR values were out of range 20.4% of the time; after nurse monitoring they were out of range 19.2% of the time (P = .115); the time between sequential INR readings also did not differ before and after implementation of nurse monitoring (23.9 vs 21.6 days, P = .789).

Nurse-led monitoring of INR is as effective as traditional physician monitoring. Advantages of nurse-led monitoring might include freeing family physicians to see more patients or to spend less time at work. It might also represent potential cost savings.