Cardiovascular screening in homeless outreach: An operationally-ethical protocol

Homeless individuals experience disproportionately high rates of cardiovascular disease (CVD), yet remain underrepresented in formal health screening programs. While community-based organizations frequently conduct outreach, few have established ethical, standardized, or replicable methods for assessing physiological risk in field settings. Existing models range from passive, meals-only outreach to costly mobile clinics with limited reach, leaving a critical gap that this low-resource, agile framework is designed to address.

To describe the development and implementation of an ethical, field-based methodology for cardiovascular screening within homeless outreach programs that emphasizes participant safety, informed consent, and operational feasibility.

A cross-sectional quality improvement needs assessment was conducted across outreach missions in San Francisco using convenience sampling. The framework integrated volunteer training, capacity screening, verbal consent procedures, vital sign collection, and predefined emergency escalation thresholds. Participants were unsheltered adults who met decisional capacity criteria and provided voluntary informed consent.

Iterative protocol refinements, including "quiet zone" policies, addressed missing data patterns inherent to this population. Among N = 116 participants screened, the framework achieved 100% fidelity in capacity and consent verification, activated emergency protocols for 9 acute events, and identified hypertensive crisis (6/59, 10.17%), nicotine use (6/33, 15.38%), and diabetes via field vitals (5/38, 13.16%).

This framework demonstrates a replicable, ethically grounded model for CVD risk screening in homeless outreach settings, achieving 100% fidelity in capacity and consent verification, a 10.17% hypertensive crisis detection rate, and scalable integration of evidence-based physiological assessment into humanitarian fieldwork.