Volume 55 | Number S2 | October 2020

Abstract List

Maria C. Raven M.D., M.P.H., M.Sc., Matthew J. Niedzwiecki PhD, Margot Kushel M.D.


To examine whether randomization to permanent supportive housing (PSH) versus usual care reduces the use of acute health care and other services among chronically homeless high users of county‐funded services.

Data Sources

Between 2015 and 2019, we assessed service use from Santa Clara County, CA, administrative claims data for all county‐funded health care, jail and shelter, and mortality.

Study Design

We conducted a randomized controlled trial among chronically homeless high users of multiple systems. We compared postrandomization outcomes from county‐funded systems using multivariate regression analysis.

Data Collection

We extracted encounter data from an integrated database capturing health care at county‐funded facilities, shelter and jails, county housing placement, and death certificates.

Principal Findings

We enrolled 423 participants (199 intervention; 224 control). Eighty‐six percent of those randomized to PSH received housing compared with 36 percent in usual care. On average, the 169 individuals housed by the PSH intervention have remained housed for 28.8 months (92.9 percent of the study follow‐up period). Intervention group members had lower rates of psychiatric ED visits IRR 0.62; 95% CI [0.43, 0.91] and shelter days IRR 0.30; 95% CI [0.17, 0.53], and higher rates of ambulatory mental health services use IRR 1.84; 95% CI [1.43, 2.37] compared to controls. We found no differences in total ED or inpatient use, or jail. Seventy (37 treatment; 33 control) participants died.


The intervention placed and retained frequent user, chronically homeless individuals in housing. It decreased psychiatric ED visits and shelter use, and increased outpatient mental health care, but not medical ED visits or hospitalizations. Limitations included more than one‐third of usual care participants received another form of subsidized housing, potentially biasing results to the null, and loss of power due to high death rates. PSH can house high‐risk individuals and reduce emergent psychiatric services and shelter use. Reductions in hospitalizations may be more difficult to realize.