Housing and supportive services for young mothers experiencing substance use disorder and homelessness: Cost-effectiveness analysis of a randomized trial

Background: Mothers experiencing homelessness and caring for young children struggle with high rates of substance use and mental health problems. A comprehensive supportive housing intervention was implemented to assist young mothers experiencing substance use disorder (SUD) and homelessness. The costeffectiveness of this intensive intervention could inform future dissemination. Methods: A cost-effectiveness analysis was conducted alongside a randomized controlled trial that lasted from May 2015 to October 2018. Mothers experiencing homelessness between the ages of 18-24 years with a SUD were randomly assigned to housing+support services (HOU + SS) (n = 80), housing-only (HOU) (n = 80), or services as usual SAU (n = 80). Using incremental cost-effectiveness ratios (ICERs), the study compared the costs of HOU + SS and HOU to SAU for three outcomes: housing stability (percent days of stable housing), substance use (percent days of substance use), and depressive symptoms (Beck Depression Inventory score). Direct intervention costs of HOU + SS and HOU from both payor and societal perspectives were estimated. Cost data were collected from detailed study financial records. Outcomes were taken from 6-month assessments. Results: The average societal cost of HOU + SS per participant was $5114 [CI 95 %, $4949-5278], while the average societal cost of HOU was $3248 [CI 95 %, $ 3,140-$3341] (2019 U.S. dollars). The calculated ICERs show that HOU was more cost-effective than HOU + SS and SAU for housing outcome. For illicit drug use, HOU + SS was more cost-effective than HOU. Finally, for depressive symptoms, neither HOU + SS or HOU were more cost effective than SAU. Conclusion: While HOU is more cost-effective for increasing housing, HOU + SS is more cost-effective for reducing illicit drug use. However, housing without improvements in substance use may not be sustainable, and supportive services are likely essential for improved well-being overall beyond the housing outcome alone.