Designing and Implementing an Electronic Patient Registry to Improve Warfarin Monitoring in the Ambulatory Setting

Abstract

Background: Warfarin requires individualized dosing and monitoring in the ambulatory setting for protection against thromboembolic disease. Yet in multiple settings, patients spend upwards of 30% of time outside the therapeutic range, subjecting them to an increased risk of adverse events. At an urban, publicly funded clinic, the electronic health record (EHR) would not support integration with extant warfarin management software, which led to the creation and implementation of an electronic patient registry and a complementary team-based work flow to provide real-time health-system-level data for warfarin patients.

Methods: Creation of the registry, which began in August 2014, entailed use of an existing platform, which could interface with the outpatient EHR. The registry was designed to help ensure regular testing and monitoring of patients while enabling identification of patients and subpopulations with suboptimal management. The work flow used for the clinic's warfarin patients was also redesigned. An assessment indicated that the registry identified 341 (96%) of 357 patients actively seen in the clinic.

Results: For the cohort of the 357 patients in the registry, the no-show rate decreased from 31% (preimplementation, August 2014-December 2014) to 21% (postimplementation, January 2015-November 2015). The ratio of visits to no-shows increased from 2.3 to 4.0 visits.

Conclusion: Design and implementation of an electronic registry in conjunction with a complementary work flow established an active tracking system that improved treatment monitoring for patients on anticoagulation therapy. Registry creation also facilitated assessment of the quality of care and laid the groundwork for ongoing evaluation and quality improvement efforts.

Figure 1. Anticoagulation Clinic Work Flow Comparison

This diagram illustrates the “current” (preimplementation) work flow for patients and the “proposed” (preimplementation) registry patient flow for in-person visits and telephone follow-up. The proposed work flow, unlike the current patient flow, among other advantages, enables the health care team to identify patients who are overdue for monitoring more efficiently. Previously, the only means to keep track of patients was through reviewing individual patient charts prior to and during the clinic visit itself.

Figure 2. No-Show Rates, Anticoagulation Clinic, August 2014–December 2015

The no-show rate of 31% for the preimplementation period (August 2014-December 2014) decreased to 21% for the postimplementation period (January 2015-November 2015).

Figure 3. Time in Therapeutic Range (TTR) Distribution, Anticoagulation Clinic, March 1, 2015– February 28, 2016

The percentage of anticoagulation clinic patients who fall into each of the five TTR quintiles are shown from the period. The mean TTR was 67.8% (range, 14.8%–100%; median, 71.2%).