Where Do Oregon Medicaid Enrollees Seek Outpatient Care Post-affordable Care Act Medicaid Expansion?

BACKGROUND: Previous studies suggest the newly Medicaid insured are more likely to use the emergency department (ED) however they did not differentiate between patients established or not established with primary care.
OBJECTIVES: To understand where Oregon Medicaid beneficiaries sought care after the Patient Protection and Affordable Care Act (PPACA) Medicaid expansion (ED, primary care, or specialist) and the interaction between primary care establishment and outpatient care utilization. RESEARCH
DESIGN: A retrospective cohort study.
SUBJECTS: Adults continuously insured from 2014 through 2015 who were either newly, returning, or continuously insured post-PPACA. MEASURES: Site of first and last outpatient visit, established with primary care status, and outpatient care utilization.
RESULTS: The odds of being established with primary care at their first visit were lower among newly [odds ratio (OR), 0.18; 95% confidence interval (CI), 0.18-0.19] and returning insured (OR, 0.22; 95% CI, 0.22-0.23) than the continuously insured. Continuously insured, new patients with primary care had higher odds of visiting the ED (OR, 2.15; 95% CI, 2.01-2.30) at their first visit than newly or returning insured. Patients established with a single primary care provider in all insurance groups had lower rates of ED visit, whereas those established with multiple primary care providers had the highest ED visit rates.
CONCLUSIONS: Most newly and returning insured Medicaid enrollees sought primary care rather than ED services and most became established with primary care. Our findings suggest that both insurance and primary care continuity play a role in where patients seek health care services.