Safety-net coverage instability during cancer care and association with overall survival.

Abstract

11090 Background: Means-tested (contingent on income) financial programs for uninsured individuals, such as Medicaid and county charity/indigent care, require periodic eligibility re-verification. A recent systematic review found that insurance coverage disruptions are associated with worse cancer stage and survival, but also highlighted that studies suffered from a limited ability to distinguish administrative lapses from eligibility-driven disruptions, and relied on single time-point measures to define longitudinal coverage. Consequently, the dynamics and clinical implications of coverage instability during cancer care are incompletely characterized. We investigated the coverage portions of the electronic health record (EHR) to overcome these issues and characterize coverage instability. Methods: We conducted a retrospective cohort study linking tumor registry records (2010–2022) to coverage verification fields from the EHR of a large county safety-net health system (2010-2024). Renewal limbo was defined as any gap between verified coverage intervals occurring > 365 days after a first verification. Multivariable logistic regression estimated odds of renewal-limbo within two years after diagnosis. Cox models estimated time to first renewal limbo and negative-binomial models for limbo duration; Prentice–Williams–Peterson models examined recurrent limbo. Two-year overall survival was estimated using a 12-month landmark design, with survival follow-up beginning at 12 months after diagnosis to ensure comparable risk windows across coverage instability groups. Results: Among 24,186 patients (56% female; 78% < age 65; 6% Medicaid, 50% County charity care; 15% breast, 8% colorectal, and 8% lung cancer), 26% experienced renewal limbo in the first year after diagnosis and 36% by the second year. Among patients with charity coverage at diagnosis who experienced renewal limbo, nearly 90% returned to charity coverage, and over two-thirds of Medicaid enrollees returned to Medicaid. Median limbo duration was 32 days (IQR, 3–220). Compared to diagnoses in 2010–2019, those diagnosed in 2020–2022 had substantially reduced odds of renewal limbo (aOR 0.29, 95% CI: 0.25-0.32) in Medicaid. In landmark analyses, uninterrupted coverage during the first year was associated with the highest survival, while patients in limbo at the time of diagnosis and at renewal limbo had the lowest survival (Table 1). Conclusions: Coverage lapses at annual renewal were common among safety-net patients treated for cancer and was largely temporary, suggesting administrative rather than eligibility-driven disruptions. Although lapses were brief, they were associated with measurably lower overall survival even 2 years after cancer diagnosis. Strong calendar-year effects in 2020-2022 suggests the influence of suspended reverification during the COVID19 public health emergency.