Primary care for new vs established Medicaid enrollees

To understand changes in primary care (PC) utilization in Medicaid and the Children's Health Insurance Program (CHIP) 3 years after the Affordable Care Act (ACA).

Secondary data analysis using Medicaid/CHIP paid claims and managed care encounters.

Pre-/post-ACA trends in total enrollment and PC visits among newly enrolled and established patients were analyzed in half-year increments from the first half of 2012 to the second half of 2016.

After ACA expansion, there was a temporary surge in new Medicaid/CHIP enrollment (which included surges in pre-ACA eligibility categories) and slow, steady growth in total enrollment. The percentage of new enrollees completing a PC visit within 90, 180, and 365 days of enrollment fell markedly in the first half of 2014 and then rebounded to pre-ACA levels thereafter. Conversely, the percentage of new enrollees remaining enrolled at 90, 180, and 365 days spiked upward in the first half of 2014 and gradually fell thereafter. Among established enrollees, PC visits per person exhibited a downward trend throughout the post-ACA period, driven mostly by a decline in the percentage of individuals with any PC visits.

The first 6 months of ACA implementation in New Jersey were marked by a surge in Medicaid/CHIP enrollment that extended beyond the ACA target population, greater enrollment retention, and apparent bottlenecks in PC delivery. After the initial surge, new enrollees used PC at rates at least as high as in the pre-ACA period, whereas established enrollees used PC at a declining rate throughout the post-ACA period. PC delivery for new enrollees may have limited the availability of services for some established enrollees.