Measuring the Impact of MEDIC’s Pulmonary Embolism Initiative: MVC Estimates Cost Savings of $3.6M Statewide
“As an emergency physician, I know that when we practice at our best, we can safely reduce overuse of CT imaging. MEDIC has been a critical partner in helping us do exactly that for pulmonary embolism—a challenging diagnosis in emergency care.” Alex Janke, MD, MHS, Quality & Analytics Consultant, MEDIC
Background
The Michigan Emergency Department Improvement Collaborative (MEDIC) is a Collaborative Quality Initiative (CQI) that aims to improve care and outcomes in Michigan emergency rooms by developing quality measures, identifying best practices, and promoting shared learning. Emergency departments (EDs) across the state can participate by submitting clinical data and undergoing evaluations based on MEDIC’s initiatives. One such initiative focused on increasing diagnostic yield in computed tomography (CT) scans for suspected pulmonary embolism (PE). The goal of this effort was to promote the use of evidence-based tools and risk calculators to help stratify patients and better tailor an approach to evaluating for this diagnosis prior to obtaining a CT.
Through comprehensive data collection and benchmarking, participating hospitals received feedback on their performance as well as resources to support implementing evidence-based strategies for PE evaluation. By minimizing negative CT scans, MEDIC’s “Diagnostic Yield in Suspected PE” initiative seeks to improve accurate diagnostic rates while reducing healthcare spending and utilization.
To help evaluate the impact of this effort, MEDIC reached out to the Michigan Value Collaborative (MVC) to leverage its robust claims-based data. Together, MVC and MEDIC assessed the impact and value of this initiative by using a difference-in-difference approach examining hospital administrative claims to measure changes in CT scan utilization rates. Specifically, MVC compared the average change in CT scan rates before and after the intervention at participating hospitals to the average change observed at non-participating hospitals. This method helped isolate the effect of the intervention, providing evidence of MEDIC’s efforts to enhance high-value, patient-centered emergency care.
Methodology
MVC and MEDIC defined the cohort as patients age 18 or older who visited the ED and were covered by Blue Cross Blue Shield of Michigan (BCBSM) PPO Commercial, BCBSM PPO Medicare Advantage (MA), Blue Care Network (BCN) HMO Commercial, BCN HMO MA, Michigan Medicaid, or Medicare Fee-For-Service (FFS). The date range for ED visits included in the analysis was 01/01/2017 – 03/25/2025 for all BCBSM/BCN plans and Medicaid, and 01/01/2017 – 09/30/2024 for Medicare FFS. The analysis excluded ED visits in which the patient died during the index event or left against medical advice, as well as ED visits with injury/trauma, CT angiograms of the abdomen/pelvis, confirmed COVID-19 (to reduce potential confounding), and confirmed acute PE-related ICD-10 diagnosis codes in any position (clinically indicated for CT). MVC used facility and professional claims to identify the ED visits in the cohort with a chest CT with intravenous (IV) contrast or angiography chest CT.
Participating hospitals were assigned to treatment cohorts based on the year the hospital first participated in related MEDIC-BCBSM Pay-for-Performance (P4P) PE metrics. Using this approach, five distinct hospital cohorts were established: 2018 (4 hospitals), 2019 (4 hospitals), 2021 (7 hospitals), 2022 (9 hospitals), and 2023 (4 hospitals). The control group consisted of 85 non-participating hospitals. ED visits at MEDIC participating hospitals that occurred after the initiative was launched (i.e., assigned on the P4P scorecard) at the specific site were considered “treated,” with the treatment period consisting of the period after the initiative was launched.
Using a difference-in-difference approach, MVC estimated changes in CT scan utilization rates at participating hospitals compared to the control group, which models what would have happened if the same hospitals had not participated in the initiative. The result is a single numerical summary called the average treatment effect on the treated (ATET). MVC estimated the number of CT scans averted as a result of the MEDIC initiative by multiplying the volume of ED visits at participating hospitals during the treatment period by the ATET. The ATET controlled for patient gender, age category, payer, 12 CMS hierarchical condition categories, high 180-day prior spending, and year. MVC also observed how the ATET changed over time.
Limitations
The analysis of the post-intervention period is more limited compared to the pre-intervention period, particularly for the 2023 cohort. This meant less data was available after the intervention for these hospitals, making the results more susceptible to random variation. Additionally, payment averages in this evaluation were calculated using price-standardized payments based on the Medicare FFS schedule. Finally, because the exact dates of intervention adoption during the treatment and evaluation period were not clearly defined, comparisons between pre- and post-intervention periods may not consistently reflect the actual duration of hospital exposure to the initiative.
Findings
There was evidence of a significant reduction in CT scans annually from 2020-2025 (Figure 1). The intervention had the largest effect on CT scan rates among treated hospitals from calendar years 2022 to 2025, and all annual ATET values used to calculate the CT scan reductions were statistically significant during that timeframe (not shown), with p-values less than or equal to p<0.01. The only year with a non-statistically significant reduction was 2019. These findings demonstrated that hospitals participating in the initiative experienced significant reductions in CT scan utilization compared to non-participating hospitals that was unlikely to be due to random variation. To estimate the number of annual averted CT scans over the course of the treatment period, MVC multiplied the total ED visit volume for treatment periods at treated hospitals by the corresponding annual ATET.
Figure 1. CT Scans Averted Annually at Participating Hospitals Due to MEDIC PE Initiative, 2018-2023*
*Although 2024 and 2025 also saw significant averted CT scans, not all payer data was available for those years, and they were therefore not included in the figure.
Overall, MVC observed a statistically significant decrease in CT scans attributable to MEDIC’s Diagnostic Yield in Suspected PE initiative over the course of MEDIC’s implementation period from 2018-2025. To estimate the total cost savings relative to non-participating hospitals, MVC used a summary ATET measure (-0.39%) applied to the total treated volume (2,304,523) to determine that 8,988 CT scans were averted during the treatment period. MVC then multiplied the estimated average cost of a CT scan based on Medicare FFS ED claims among MEDIC hospitals ($403) by the number of CTs averted (8,988). This resulted in an estimated $3.6M in price-standardized cost savings (Table 1). The analysis demonstrated that MEDIC sites delivered significant net savings for their patients, BCBSM, and hospitals in MI.
Table 1. Estimated Total Dollars Averted
