The Effect of a Housing First Intervention on Acute Health Care Utilization among Homeless Adults with Mental Illness: Long-term Outcomes of the At Home/Chez-Soi Randomized Pragmatic Trial

We assessed the effects of the Toronto Site Housing First (HF) intervention on hospitalizations and emergency department (ED) visits among homeless adults with mental illness over 7 years of follow-up. The Toronto Site is part of an unblinded multi-site randomized pragmatic trial of HF for homeless adults with mental illness in Canada, which followed participants up to 7 years. Five hundred seventy-five participants were recruited and classified as having high (HN) or moderate need (MN) for mental health support services. Each group was randomized into intervention (HF) and treatment as usual groups, and 567 (98.6%) consented to link their data to health administrative databases. HF participants received a monthly rent supplement of $600 (Canadian) and assertive community treatment (ACT) support or intensive care management (ICM) support based on need level. Treatment as usual (TAU) participants had access to social, housing, and health services generally available in the community. Outcomes included all-cause and mental health-specific hospitalization, number of days in hospital, and ED visit. We used GEE models to estimate ratio of rate ratios (RRR). The results showed HF with ACT had no significant effect on hospitalization rates among HN participants, but reduced the number of days in hospital (RRR = 0.32, 95% CI 0.16-0.63) and number of ED visits (RRR = 0.57, 95% CI 0.34-0.95). HF with ICM resulted in an increase in the number of hospitalizations (RRR = 1.69, 95% CI 1.09-2.60) and ED visit rates (RRR = 1.42, 95% CI 1.01-2.01) but had no effect in days in hospital for MN participants. Addressing the health needs of this population and reducing acute care utilization remain system priorities. Trial registration: http://www.isrctn.com/identifier: ISRCTN42520374 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11524-021-00550-1.