Warfarin management using point-of-care testing in a university-based internal medicine resident clinic

The primary endpoint was to determine whether point-of-care (POC) International Normalization Ratio (INR) testing would increase the percentage of patients in the therapeutic range. The secondary endpoint was to determine how POC Testing (POCT) would affect the time to intervention (the amount of time it took to contact a patient who had an INR outside the therapeutic range and make the appropriate warfarin adjustment).

Over an 11-month time period, the authors implemented an anticoagulation-focused quality improvement initiative based on the internal medicine resident continuity clinic. The initiative was designed as a single site before and after study.

The proportion of INR values within the therapeutic range before the implementation of POCT (predesign phase) was 25%. After the implementation of POCT (postdesign phase), the percentage of therapeutic INR was 50% (P = 0.005). The time to intervention in the predesign phase was 4 days while intervention was accomplished during the same visit that the blood was sampled in the postdesign phase of this study. The number needed to treat was 4 to obtain a therapeutic INR.

The results of this quality improvement study showed significant improvement in the percentage of patients who were in the therapeutic range with the use of POCT. Time to intervention was also markedly improved with the addition of POCT. The authors believe that this is the first study showing such results in an internal medicine academic clinic.