Root Cause Analysis of Adverse Events in an Outpatient Anticoagulation Management Consortium

Background: A number of factors can lead to adverse events (AEs) in patients taking warfarin. Performing a root cause analysis (RCA) of serious AEs is one systematic way of determining the causes of these events.

Methods: Multidisciplinary teams were formed at Michigan Anticoagulation Quality Improvement Initiative (MAQI²) sites with organized anticoagulation management services (AMS). Medical records from patients who suffered serious AEs (major bleed, embolic stroke, venous thromboembolism) were reviewed, and AMS staff were interviewed to determine the root cause using the "5 Whys" technique. More than 600 patients had an AE and underwent screening by trained RNs. Of these, 79 required full review by a multidisciplinary panel. All potential contributing factors (comorbidities, concurrent medications, current protocols) were assessed to determine the main factor that caused the AE.

Results: Full RCA was completed in 79 cases. The main contributing factor was identified in 69/79 (87%) cases. Most identified AEs, 55/69 (80%), were due to patient-specific factors such as comorbidities. Patient-to-provider and provider-to-provider communication accounted for 16/69 (23%) of events and was the second most common cause. Other causes included protocol non-adherence and technology/equipment issues. After each detailed review, the multidisciplinary panel recommended system changes that addressed the primary cause.

Conclusion: The majority of severe AEs for patients taking warfarin were related to nonmodifiable patient-related issues. The remaining AEs were primarily due to patient-to-provider and provider-to-provider communication issues. Methods for improving communication need to be addressed, and methods for more effective patient education should be investigated.