Medicaid expansion and treatment for opioid use disorders in Oregon: an interrupted time-series analysis

The study examined the association of the Affordable Care Act's 2014 Medicaid expansion on the use of psychosocial services and pharmacotherapies for opioid use disorders among Oregon Medicaid recipients.

Logistic regression analysis examined utilization of care before (January 1, 2010-December 31, 2013) and after Medicaid expansion in Oregon (January 1, 2014-December 31, 2016).

Adult membership in the Oregon Health Plan (Medicaid) increased 180% following Medicaid expansion (2013 = 172,539; 2014 = 482,081) and the number with a diagnosis of OUD nearly doubled (2013 = 6808; 2014 = 13,418). More individuals received psychosocial services (2013 = 4714; 2014 = 8781) and medications (2013 = 3464; 2014 = 6093) for opioid use disorder. The percent of patients receiving psychosocial services (69% to 65%) and the percent of individuals receiving pharmacotherapy (57% to 45%) declined primarily because of a decline in the proportion receiving care in an opioid treatment program (2013 = 41%; 2014 = 33%). Odds of accessing any psychosocial service increased by 8% per year from 2010 to 2013 (AOR = 1.08; 95% CI 1.06-1.11) with an 18% immediate decline associated with Medicaid expansion in 2014 (AOR = 0.82; 95% CI 0.76-0.87). Following Medicaid expansion, the odds of accessing psychosocial services increased 8% per year (2014 through 2016) (AOR = 1.08; 95% CI 1.06-1.11). Use of medications for opioid use disorder found no change in the odds of use in the years prior to Medicaid expansion, an immediate 36% (AOR = 0.64; 95% CI 0.60-0.68) decline in 2014, and a 13% increase per year in 2015 and 2016 (AOR = 1.13; 95% CI 1.09-1.16).

The number of Medicaid recipients with an opioid use disorder who received psychosocial and pharmacological services increased substantially following Oregon's Medicaid expansion in 2014. There was a decline, however, in the proportion of individuals with an opioid use disorder receiving care in opioid treatment programs.