A cost-effectiveness analysis of a housing and recovery program for people with severe and persistent mental illnesses and precarious housing

Abstract

ABSTRACT The Doorway program supports people with Serious and Persistent Mental Illnesses (SPMIs) receiving care within Victoria’s public mental health system and who are precariously housed. This paper reports on its cost-effectiveness. The study design was difference-in-differences involving a Treatment-As-Usual comparison group (TAU) using deidentified client records. The primary outcome measure was the proportion of days of secure housing per participant during the study and pre-study periods. Similarly, health service usage was also extracted from participants’ records. The cost of public mental health service usage was then estimated, including using governmental published data. The program’s Incremental Cost Effectiveness Ratio (ICER) and Cost-effectiveness Acceptability Curve were estimated using the bootstrap method. An ICER threshold of Australian $50,000 per additional person housed (hereafter A$) at 100% was set to determine cost-effectiveness and the probability of cost effectiveness at A$50,000. Mean total costs (secure housing and mental health service usage) were greater for the Doorway group compared to the TAU group (A$22,987). Mean percentage of days securely housed was also greater for the Doorway group (by 45.4%). The ICER value was A$50,613, the probability of this being 83.1%. The Doorway intervention was both more costly and more effective. Its cost-effectiveness approximated the pre-specified ICER threshold.