Project Summary/Abstract: Dr. Benjamin Han's long-term goal is to become a leader in aging and addiction research with expertise on developing chronic care delivery models coordinated within substance use treatment for older adults. This career award will support Dr. Han towards this goal by providing additional training and completing the proposed mentored research to continue his career development into an independent clinician investigator. The proposed research addresses a critical knowledge gap in the setting of an epidemic of older adults with substance use disorders: the current healthcare patterns, burden of chronic disease, and attitudes and barriers towards chronic disease management of older adults with opioid use disorders (OUD). Although it is recognized that older adults with OUD are often medically and socially complex, very little is known regarding the specific health status and needs of this vulnerable population. Dr. Han's proposed career development plan will allow him to address this knowledge gap by working with a team of mentors as well as with the County of San Diego’s Behavioral Health Services who will collaborate on the following training goals: (1) to achieve expertise in advanced quantitative methods and the use of large administrative datasets for addiction health services research; (2) to develop skills in qualitative research theory and practice; and (3) attain proficiency and experience in the development of a care intervention, and the associated skills in assessing feasibility, sustainability, program evaluation, and implementation research. Dr. Han will attain these training goals with guidance from his mentorship team complemented by formal coursework and seminars, and by conducting a research agenda that uses a mixed methods approach with the following specific aims: (1) describe the prevalence and risk factors for high utilization of acute healthcare, high medical costs, multiple chronic conditions, and mortality among older adults with OUD; (2) examine staff and patient attitudes, acceptance, feasibility, and barriers regarding the integration of geriatric models of care into opioid treatment programs; (3) develop and pilot an evidence-based geriatric care model for geriatric conditions and chronic disease management for older adults with OUD. This will set a future research agenda for widely integrating an evidence-based model of geriatric-based chronic disease assessment and management into existing substance use treatment programs.