Primary care appointment availability for new Medicaid patients increased after Medicaid expansion in Michigan.

The Affordable Care Act expands health insurance coverage to millions of Americans, but the availability of health care services for the newly insured population remains uncertain. We conducted a simulated patient (or "secret shopper") study to assess primary care appointment availability and wait times for new patients with Medicaid or private insurance before and after implementation of Michigan's Medicaid expansion in 2014. The expansion, which was made possible through a section 1115 waiver, has a unique requirement that new beneficiaries must be seen by a primary care provider within 60-90 days of enrollment. During a period of rapid coverage expansion in Michigan, we found that appointment availability increased 6 percentage points for new Medicaid patients and decreased 2 percentage points for new privately insured patients, compared to availability before the expansion. Wait times remained stable, at 1-2 weeks for both groups. Further research is needed to determine whether access to primary care for newly insured patients will endure over time.