Effect of Patient Self-Testing on Chronic Anticoagulation

Purpose: The primary aim of this quality improvement project is to evaluate the safety of patient self-testing (PST), with a home INR monitor, and to determine patients’ satisfaction of their anticoagulation management. Based on the results of this evaluation, a protocol may be developed that will allow for identification of patients who qualify for at Virginia Commonwealth University Health System (VCUHS).

Methods: This evaluation is a retrospective, electronic medical record review that includes patients enrolled in the anticoagulation clinic at VCUHS from 2008 through 2011. Subjects for this quality improvement project are patient’s ≥18 years of age who were managed in the anticoagulation clinic for at least 3 months prior to being transitioned to PST. The primary outcome, or the time in therapeutic range pre- and post-transition, was compared.  Secondary outcomes included the percent of time spent in therapeutic range (TTR), number of INR readings, and incidence of undercoagulation and overanticoagulation. In addition, a patient satisfaction survey, using the validated Duke Anticoagulation Satisfaction Scale (DASS), was mailed to the patients.

Results: Medical records of 104 patients, initially managed in the anticoagulation clinic and then transitioned to PST, were identified and reviewed.  Eighty patients were included in the study analysis, and forty-five returned the survey questionnaire.  The percent TTR of INR values obtained during PST was significantly higher than the clinic management phase, 66% vs 51%, respectively ( p < 0.0001).  INR values obtained during the PST phase had a higher rate of percent under-anticoagulation compared to during the clinic phase (35% vs 23%, p<0.0001).  No other statistically significant difference was found for any other secondary outcomes.

Conclusion: Our study demonstrated that INR values using a PST device can be a safe and efficacious alternative to anticoagulation management done in the physician or specialty anticoagulation clinics.