BACKGROUND: Efforts to integrate substance use disorder treatment into primary care settings are growing. Little is known about how well primary care settings can sustain treatment delivery to address substance use following the end of implementation support.

METHODS: Data from two clinics operated by one multi-site federally qualified health center (FQHC) in the US, including administrative data, staff surveys, interviews, and focus groups, were used to gather information about changes in organizational capacity related to alcohol and opioid use disorder (AOUD) treatment delivery during and after a multi-year implementation intervention was executed. Treatment practices from the intervention period were compared to practices after the intervention period to examine whether the practices were sustained. Data from staff surveys and interviews were used to examine the factors related to sustainment.

RESULTS: The two clinics sustained multiple components of AOUD care 1 year following the end of implementation support, including care coordination, psychotherapy, and medication-assisted treatment. Some of the practices were modified over time, for example, screening became less frequent by design, while use of care coordination and psychotherapy for AOUDs expanded. Participants identified staff training and funding for medications as key challenges to sustaining treatment.

CONCLUSIONS: Following a multi-year implementation intervention, a large FQHC continued to deliver AOUD treatment. Access to external funding and staff support appeared to be critical elements for sustaining care over time.