Health Care Utilization Among Homeless-Experienced Adults Who Were Seen by a Mobile Addiction Program in Boston, MA: A Quasi-Experimental Study

Abstract

Introduction: People experiencing homelessness have a high burden of substance use disorders yet are often not well engaged in the healthcare system. This study evaluated the effect of a mobile addiction program, an innovative method to improve access to care in this population, on health care utilization.

Methods: We evaluated adults ( > 18 years) who had > 1 encounter with the mobile addiction program in Boston, MA from 1/16/18-1/15/19. We developed a one-to-one propensity score matched control cohort of adults with a diagnosis of opioid use disorder who received care at Boston Health Care for the Homeless Program during the same timeframe who did not interact with the mobile program. The primary outcome was the number of outpatient visits; the secondary outcomes were the number of hospitalizations and emergency department (ED) visits, assessed using Massachusetts Medicaid claims data. Based on a difference-in-differences analytic framework, we used Poisson regression models to examine the number of outpatient, inpatient, and ED visits before and after the index visit with the mobile program relative to the propensity-matched control cohort.

Results: Of the 138 adults who engaged with the mobile addiction program between 1/16/18 and 1/15/19, 29.7% were female, 16.7% were Black, 8.0% were Latinx, 68.1% were White, and the mean age was 40.4 years (SD 12.2). The yearly mean number of outpatient visits increased from 11.5 to 12.1 (p=0.42) in the mobile program cohort, whereas it decreased from 12.4 to 9.9 (p=0.12) in the control cohort (p diff-in-diff =0.09). In the mobile program cohort, the yearly mean number of hospitalizations increased from 2.2 to 3.0 (p=0.04), whereas it remained stable at 2.5 per year (p=0.82) in the control cohort (p diff-in-diff =0.29). In the mobile program cohort, the yearly mean number of ED visits increased from 5.4 to 6.5 (p=0.04) and increased from 5.7 to 5.8 (p=0.82) in the control cohort (p diff-in-diff =0.25).

Conclusions: The mobile addiction program for homeless-experienced adults did not significantly alter health care utilization patterns in the first year relative to matched controls. Further research in larger samples or using a broader set of outcomes is needed to quantify the benefits of this innovative care delivery model.

Note:
Funding Information: This work was supported by the Kraft Center for Community Health; the National Institutes of Health (K12DA043490); the Division of General Internal Medicine at Massachusetts General Hospital (MGH); the MGH Research Scholars Program; and the National Institutes of Health (DP5-OD024564).

Declaration of Interests: Travis Baggett receives royalties from UpToDate. The other authors have no conflicts of interest to disclose.

Ethics Approval Statement: This study was approved by the Mass General Brigham Human Research Committee Institutional Review Board.

Keywords: People experiencing homelessness, opioid use disorder treatment, mobile van program