Currently submitted to: JMIR Research Protocols
Date Submitted: Feb 26, 2026
Open Peer Review Period: Mar 3, 2026 - Apr 28, 2026
(currently open for review)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Systemwide evaluation of field medicine programs in Los Angeles County: Protocol for a mixed methods longitudinal observational study
ABSTRACT
Background:
Background:
People experiencing homelessness (PEH) face high morbidity and unmet health care needs. To address these gaps, healthcare providers across the United States are increasingly adopting “field medicine” models that deliver mobile health services in shelters, homeless encampments, mobile clinics, and other community settings. Despite their expanding use, systematic evaluations of field medicine programs remain limited.
Objective:
Objectives: This paper describes a protocol for a mixed methods evaluation of field medicine for PEH across Los Angeles (LA) County, California.
Methods:
Methods:
PEH receiving field medicine were recruited into an ongoing longitudinal study of the LA County’s unhoused population; a subset of participants in the existing probability-sampled cohort serve as the comparison group. Using monthly online survey data and a quasi-experimental design, we examine who accesses field medicine, how patients use and perceive care, and its impact on health and service engagement. We also conduct participant observation of field medicine teams to document patient–provider interactions and care coordination and carry out semi-structured interviews with providers, patients, and non-patients. Quantitative survey and qualitative findings will be integrated to identify convergence, complementarity, and explanatory insights.
Results:
Results:
Recruitment of PEH receiving field medicine occurred between August 2024 and October 2025. Among 847 individuals referred from field medicine, 749 were eligible and 436 completed the first monthly survey and were enrolled. For the comparison group, 902 of the 1,413 participants ever enrolled in the existing cohort completed a survey during the field medicine recruitment period and met eligibility criteria. Participant observation included 82 field visits (≈500 hours) across diverse service locations and more than 300 patient–clinician interactions. Semi-structured interviews were conducted with 15 providers, 23 field medicine patients, and 12 non-patients.
Conclusions:
Conclusions:
This study represents one of the first large-scale mixed-methods evaluations of field medicine. With increasing health threats from criminalization, climate-related events, and other socioenvironmental hazards, field medicine may mitigate health risks and improve systems engagement for PEH. Findings will provide rigorous evidence to inform service delivery and policy decisions.
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.