Patterns and Predictors of MCO Coverage Gaps In Illinois: Subgroup Disparities before and after COVID-19, 2018-2024

Background and Purpose

Managed care organization (MCO) enrollment continuity supports care coordination and continuity of provider relationships, as well as simplicity for enrollees. Thus, it is critical for Medicaid beneficiaries. To prevent disruptions, Illinois implemented the Continuity of Care (CoC) Demonstration, extending the automatic MCO reinstatement window from 60 to 90 days. This study addresses two research questions: (1) What are the salient post-gap coverage trajectories among MCO enrollees, and how did these patterns differ between the pre-CoC (2018-2019) and post-CoC (2023-2024) periods? (2) How does the risk of MCO coverage gap onset vary across subgroups of post-CoC enrollees, defined by age, sex, race/ethnicity, and urbanicity? Thus, the study identifies which enrollee subgroups remained most vulnerable to coverage disruptions despite the demonstration’s provisions, offering population-specific insights for practitioners and policymakers working to advance equitable Medicaid access.

Methods

This study uses individual-level administrative data from the Illinois Medicaid Enterprise Data Warehouse. The analytic sample includes MCO beneficiaries during the pre-public health emergency (PHE) baseline (2018-2019) and the post-PHE emergency unwinding period (April 2023-December 2024), excluding the PHE period (2020 to early 2023), when the federal continuous enrollment mandate suspended typical disenrollment processes. Coverage gap onset is defined as an administrative interruption of 60-90 days, excluding gaps attributable to death, income changes, or out-of-state relocation. Post-gap trajectories (reinstatement into the same MCO, transition to a different MCO, or transition to Fee-For-Service Medicaid) are examined descriptively. Discrete-time hazard models estimate monthly probabilities of gap onset, with age group, sex, race/ethnicity, and urbanicity entered as main effects and as interaction terms within the policy period.

Results

Among enrollees who experienced a 60–90 day gap, post-gap trajectories shifted markedly between 2018 and 2023. The proportion reinstating into the same MCO increased from 27.52% in 2018 to 84.30% in 2023, while transitions to a different MCO declined from 32.82% to 0.95%, and transitions to FFS Medicaid declined from 39.66% to 14.75%. Hazard model estimates revealed significant subgroup heterogeneity in gap onset risk. Adults aged 19-64 exhibited the highest gap onset probabilities, potentially reflecting their greater exposure to income fluctuations and Medicaid eligibility thresholds compared to children and older adults. Gap onset risk among Hispanic beneficiaries disproportionately increased during the 2023 unwinding period relative to other racial and ethnic groups. Differences by sex were minimal and not statistically significant.

Conclusion

The observed trends suggest the CoC Demonstration’s 90-day reinstatement window supported more stable MCO enrollment for numerous beneficiaries. However, the demonstration’s benefits were unevenly distributed. Working-age adults (19-64) faced the highest gap onset risk, suggesting that income-related eligibility volatility may limit the reach of administrative simplification policies for this population. Hispanic beneficiaries also showed sharper declines in reinstatement rates during the 2023 unwinding period. These findings suggest that sustaining coverage continuity will require population-specific strategies beyond structural protections, including targeted outreach and streamlined renewal processes for working-age and Hispanic enrollees.