Medicaid cost outcomes associated with brief interventions for substance use disorders among patients in hospital emergency departments

Medical costs are a significant economic problem associated with substance use disorders. Working age disabled Medicaid clients who have substance use disorders are notably expensive to the Medicaid system. A Screening, Brief Intervention, Referral, and Treatment (SBIRT) Project was implemented in nine hospital Emergency Departments (ED) in Washington State. State administrative records were used to compare changes in Medicaid costs for working age disabled clients who received a brief intervention (n=1299) to changes in costs for similar clients treated in an ED but who did not receive an intervention (n=8823), using a two-stage regression model that controlled for demographics, prior alcohol or drug use, baseline chronic disease risk scores, prior medical service use, diagnoses, length of Medicaid eligibility, and costs associated with index ED visit. Using propensity scores as a covariate and a difference-of-differences approach, changes in Medicaid costs before and after the brief intervention were compared to changes in Medicaid costs before and after an index ED visit for the comparison group.

Overall Medicaid costs were lower by $177 per member per month (pmpm) for disabled clients who received at least a brief intervention compared to those who did not (p=.106). Reductions in overall Medicaid costs were due to declines in inpatient hospitalization costs associated with subsequent ED admissions (p = .004). Further analyses revealed that cost changes were most striking for patients treated for injuries (-$467 pmpm; p=.03). Findings suggest that SBIRT may be an effective means for lowering subsequent medical costs for these high-cost clients.