Health Care Utilization among Homeless-Experienced Adults Who Were Seen by a Mobile Addiction Health Clinic in Boston, Massachusetts: A Quasi-Experimental Study

Background: Mobile health clinics improve access to care for marginalized individuals who are disengaged from the healthcare system. This study evaluated the association between a mobile addiction health clinic and health care utilization among people experiencing homelessness. Methods: Using Medicaid claims data, we evaluated adults who were seen by a mobile addiction health clinic in Boston, Massachusetts from 1/16/18-1/15/19 relative to a propensity score matched control cohort. We evaluated both cohorts from four years before to one year after the index visit date with the mobile clinic. The primary outcome was the number of outpatient visits; secondary outcomes were the number of hospitalizations and emergency department (ED) visits. We used Poisson regression to compare changes in outcomes from before to after the index date in a quasi-experimental design. Results: 138 adults were seen by the mobile clinic during the observation period; 29.7% were female, 16.7% were Black, 8.0% Hispanic, 68.1% White, and the mean age was 40.4 years. The mean number of mobile clinic encounters was 3.1. The yearly mean number of outpatient visits increased from 11.5 to 12.1 (p = 0.43; p(diff-in-diff) = 0.15), the number of hospitalizations increased from 2.2 to 3.0 (p = 0.04; p(diff-in-diff) = 0.87), and the number of ED visits increased from 5.4 to 6.5 (p = 0.04; p(diff-in-diff) = 0.40). Conclusions: The mobile addiction health clinic was not associated with statistically significant changes in health care utilization in the first year. Further research in larger samples using a broader set of outcomes is needed to quantify the benefits of this innovative care delivery model.