Reducing low-value ED coags across 11 hospitals in a safety net setting

Prothrombin/international normalized ratio and activated partial thromboplastin time (PT/INR and aPTT) are frequently ordered in emergency departments (EDs), but rarely affect management. They offer limited utility outside of select indications. Several quality improvement initiatives have shown reduction in ED use of PT/INR and aPTT using multifaceted interventions in well-resourced settings. Successful reduction of these low-value tests has not yet been shown using a single intervention across a large hospital system in a safety net setting. This study aims to determine if an intervention of two BPAs is associated with a reduction in PT/INR and aPTT usage across a large safety net system.

This initiative was set at a large safety net system in the United States with 11 acute care hospitals. Two Best Practice Advisories (BPAs) discouraging inappropriate PT/INR and aPTT use were implemented from March 16, 2022-August 30, 2022. Order rate per 100 ED patients during the pre-intervention period was compared to the post-intervention period on both the system and individual hospital level. Complete blood count (CBC) testing served as a control, and packed red blood cell transfusions served as a balancing measure. An interrupted time series regression analysis was performed to capture immediate and temporal changes in ordering for all tests in the pre and post-intervention periods.

PT/INR tests exhibited an absolute decline of 4.11 tests per 100 ED encounters (95% confidence interval -5.17 to -3.05; relative reduction of 18.9%). aPTT tests exhibited absolute decline of 4.03 tests per 100 ED encounters (95% CI -5.10 to -2.97; relative reduction of 19.8%). The control measure, CBC, did not significantly change (-0.43, 95% CI -2.83 to 1.96). Individual hospitals showed variable response, with absolute reductions from 2.02 to 9.6 tests per 100 ED encounters for PT/INR (relative reduction 12.1%-30.5%) and 2.07 to 10.04 for aPTT (relative reduction 12.1%-31.4%). Regression analysis showed that the intervention caused an immediate 25.7% decline in PT/INR and 24.7% decline in aPTT tests compared to the control measure. The slope differences (rate of order increase pre vs post intervention) did not significantly decline compared to the control.

This BPA intervention reduced PT/INR and aPTT use across 11 EDs in a large, urban, safety net system. Further study is needed in implementation to other non-safety net settings.