Impact of an Intensive Outpatient Clinic Model on Health Care Utilization and Cost.

OBJECTIVE: To evaluate the impact of an intensive outpatient clinic (IOC) model on health care utilization and costs among medically and behaviorally complex adults enrolled in a Medicaid managed care organization. STUDY DESIGN: A retrospective cohort study using interrupted time series (ITS) and Bayesian structural time series (BSTS) analysis was conducted to examine changes in health care use and costs before and after IOC enrollment. METHODS: Observational claims data from 2015 to 2023 were analyzed for 150 adults who enrolled in an IOC between 2017 and 2023. Outcomes included total, medical, and pharmacy costs; hospital admissions; and emergency department (ED) visits, tracked 24 months before and after enrollment. RESULTS: Mean annual health care spending decreased by 43% 2 years after IOC enrollment. ITS analysis showed significant monthly reductions in total spending (-$142; 95% CI, -$242 to -$42; P  < .01) and medical costs (-$129; 95% CI, -$229 to -$29; P  = .01). Hospital admissions and ED visits declined by 36 (95% CI, -58 to -13; P  < .01) and 25 (95% CI, -35 to -16; P  < .01) per 1000 patients per month, respectively. BSTS estimates showed a 6% decrease in total spending, a 10% decrease in medical costs, and a 28% decrease in ED visits. CONCLUSIONS: The IOC was associated with significant reductions in health care costs and utilization among medically and behaviorally complex adults. Scalable interventions such as an IOC may help improve care coordination and reduce costs for high-risk Medicaid populations.