Association of Eliminating Waiting Periods for the Children's Health Insurance Program with Children's Enrollment.

Objectives: Prior to the Affordable Care Act (ACA), over two-thirds of states mandated that children had to be uninsured for set periods of time before enrolling in the Children's Health Insurance Program (CHIP), referred to as waiting periods. The ACA required that waiting periods could not exceed 90 days, leading states to reduce and eliminate waiting periods in response. This study aimed to examine the association between state waiting period elimination under the ACA with children's enrollment in CHIP.

Methods: We used 2010-2019 annual state enrollment data from the Centers for Medicare & Medicaid Services to calculate the proportion of children enrolled in CHIP among 20 states that eliminated waiting periods compared to 14 who maintained them. We estimated difference-in-difference models to assess the association between waiting period elimination with children's CHIP enrollment.

Results: In states that eliminated waiting periods, there were significant increases from 10.86% (95% CI: 9.51-12.21) of children enrolled in CHIP in the pre-policy period to 13.43% (95% CI: 12.21-14.66) after the ACA policy change. In adjusted difference-in-difference models, state waiting period elimination was associated with a 1.75% point (95% CI: 0.43-3.11) increase in children's enrollment in CHIP relative to states that maintained waiting periods, representing a 16% enrollment increase from pre-policy baseline levels.

Conclusions: Waiting period elimination under the ACA led to modest but significant increases in CHIP enrollment among children. Our results suggest potential CHIP enrollment benefits from the elimination of waiting periods that were maintained in 9 states.