# Utilization and Costs of Mobile Medical Units for Veterans Experiencing Homelessness

## TL;DR

Mobile medical units for homeless veterans increased primary care and mental health access but raised overall healthcare costs.

## Contribution

This study evaluates the impact of mobile medical units on healthcare utilization and costs for homeless veterans.

## Key findings

- MMUs increased primary care and mental health services use among homeless veterans.
- Emergency department and homeless program utilization also increased with MMUs.
- Total healthcare costs rose, with fewer inpatient stays for substance use and domiciliary care.

## Abstract

How is implementation of mobile medical units (MMUs) associated with health care utilization and costs for veterans experiencing homelessness?

In this cohort study of 2700 participants, compared with usual care, implementation of MMUs was associated with increased utilization of primary care and mental health intensive case management and decreased use of inpatient substance use disorder and domiciliary care. MMUs were also associated with more utilization of homeless programs and emergency department care, and higher total health care costs increased.

These findings suggest that MMUs reach patients with greater needs and increase access to primary care and mental health services at higher costs.

This cohort study investigated the implementation of mobile medical unit care vs traditional care for veterans experiencing homelessness and assessed the associated costs and utilization of services.

The Veterans Affairs (VA) health care system Homeless Patient Aligned Care Teams (HPACT) program began staggered deployment of mobile medical units (MMUs) to 24 VA medical centers in late 2023 to increase outreach and health care access in community settings for veterans experiencing homelessness.

To examine the early association between MMU implementation and the use of outpatient and inpatient services and costs among veterans experiencing homelessness.

This longitudinal cohort study was performed at 24 HPACT sites from October 1, 2021, to March 30, 2025. Participants included veterans experiencing homelessness who used MMU care. Changes in utilization and costs in each fiscal quarter before and after site MMU implementation were estimated for patients treated by MMU relative to those receiving usual care.

MMUs providing primary care and other services in community settings.

VA outpatient visits by type of care, VA inpatient stays by type of care, and VA outpatient, inpatient, and total costs of care, analyzed using linear difference-in-differences and event study models. Sensitivity analyses included a propensity score–matched comparison group and comparisons of all veterans experiencing homelessness in MMU sites and other HPACT sites.

A total of 2700 patients who used MMU care were included in the analysis (mean [SD] age, 60.5 [12.6] years). Of these, 2523 patients (93%) were male and had a mean (SD) Elixhauser comorbidity score of 3.3 (2.8). Per fiscal quarter, patients using MMU care had increases in mean number of visits for primary care (0.43; 95% CI, 0.30-0.56), homeless programs (1.40; 95% CI, 1.05-1.76), mental health intensive case management (0.03; 95% CI, 0.01-0.06), and emergency department care (0.06; 95% CI, 0.03-0.10); decreased mean inpatient stays for substance use disorders (−0.002; 95% CI, −0.004 to −0.0004) and domiciliary care (−0.002; 95% CI, −0.004 to −0.001); and increased mean total costs ($1724; 95% CI, $1172-$2276) compared with those receiving usual care after MMU implementation.

In this cohort study of veterans experiencing homelessness, patients receiving MMU care had small increases in primary care, mental health intensive case management, emergency department, and housing and other homeless services and few decreases in inpatient care at higher health care costs. MMUs may not reduce all types of acute care, but they may be an effective modality to reach veterans experiencing homelessness with access barriers and greater complexity and needs for care.