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Cost Analysis of an Outpatient MRI Pathway for Optic Disc Edema: A Time-Driven Activity-Based Costing Approach
Florian H Guillot1, James Davis2, Divya Manikandan3
1From the Division of Neuro-Ophthalmology (F.H.G., J.D., J.B., M.G.C., A.R.C., A.D.H.), Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA; Casey Eye Institute (F.H.G.), Oregon Health & Science University, Portland, Oregon, USA.
Objective:
To compare the costs and efficiency of an outpatient STAT neuroimaging pathway against traditional emergency department (ED)-based neuroimaging for patients with optic disc edema.
Design:
Retrospective cost analysis using time-driven activity-based costing (TDABC) methodology.
Subjects:
One-hundred twenty-nine patients with optic disc edema, seen at the Wilmer Eye Institute, underwent expedited neuroimaging between November 2018 and February 2024.
Methods:
We identified patients who received neuroimaging for optic disc edema either through the ED or a dedicated outpatient STAT neuroimaging pathway implemented in November 2020. Process maps were developed for each pathway. TDABC methodology was used to calculate the cost of personnel, equipment, facilities, and consumables based on resource-specific capacity cost rates and time utilization data extracted from the electronic medical record and staff interviews.
Main Outcome Measures:
The primary outcome was the total cost of neuroimaging via the STAT outpatient versus ED pathway. Secondary outcomes included total visit duration and the distribution of costs across different resource categories.
Results:
The outpatient STAT pathway was significantly less costly than the ED pathway. The median total cost per patient was $285 for the STAT pathway compared with $355 for the combined ED pathway (P < .001), representing a 20% cost reduction. This savings was primarily driven by lower personnel ($154 vs $220; P < .001) and facilities costs ($1.30 vs $6.70; P < .001). The median imaging visit duration was 70% shorter in the STAT pathway (1.93 hours) compared with the ED (6.47 hours; P < .001). This time difference was largely attributable to the pre-MRI phase, which was over 20 times shorter in the outpatient setting (0.22 vs 4.80 hours; P < .001).
Conclusions:
An outpatient STAT neuroimaging pathway is a cost- and time-saving alternative to the ED for expedited neuroimaging in select patients presenting with optic disc edema. The novel use of TDABC methodology in this setting allowed for an unbiased assessment of healthcare costs, independent of local reimbursement structures or payor variability. Additionally, a detailed process map of the imaging workflow facilitated identification of inefficiencies. Together, these methods provide a reliable framework to optimize care pathways, substantially reduce healthcare costs, and alleviate burden on EDs.
