An analysis published Aug. 31 by Epic Research found the proportion of U.S. health care encounters billed as self-pay increased across four care settings between early 2022 and mid-2026, while Medicaid's share of encounters declined in each setting studied. The research examined more than 550 million encounters recorded in Cosmos, Epic’s research dataset, spanning January 2022 through June 2026.
Cosmos includes records from a collaboration of Epic health systems representing over 310 million patient records across roughly 2,200 hospitals and 50,000 clinics in all 50 states and several international sites. For each quarter in the study window, researchers calculated the share of encounters whose primary expected payer was self-pay, Medicaid, traditional Medicare, Medicare Advantage or commercial/other coverage in four care settings: the emergency department, inpatient admissions, births and primary care.
The most pronounced rise in self-pay occurred in the emergency department (ED). ED self-pay visits increased from 5.5% of encounters in the first quarter of 2022 to 7.6% in the second quarter of 2026 — the steepest growth among the four settings tracked. Inpatient admissions’ self-pay share climbed from 1.9% to 2.6% over the same period, and births rose from 0.8% to 1.3%. Primary care showed only a small increase in self-pay, moving from 1.8% to 1.9%.
At the same time, Medicaid's share declined across all settings. Births consistently carried the highest Medicaid share but fell from 23.1% to 21.5%. The ED experienced the largest Medicaid decline, from 18.2% to 16.1%. Inpatient admissions fell from 13.2% to 11.7%, and primary care dropped from 11.4% to 10.3%.
A closer look at ED encounters showed two payer categories increased between 2022 and 2026: self-pay and Medicare Advantage. Medicare Advantage rose from 10.3% to 13.0% of ED encounters. By contrast, traditional Medicare, Medicaid and commercial/other coverage all fell during the period. Commercial/other slipped from 53.1% to 51.3%, and traditional Medicare declined from 12.8% to 11.9%.
Investigators linked the observed changes in payer mix to the end of the federal continuous-enrollment provision for Medicaid, which lapsed March 31, 2023. That provision had kept nearly all Medicaid beneficiaries covered during the COVID-19 pandemic without routine eligibility checks. After it expired, states began a staggered process of redetermining eligibility and terminating coverage for beneficiaries who no longer qualified or who did not complete renewal paperwork. Because states controlled the timing of these eligibility reviews, the unwinding occurred on a state-by-state schedule beginning in spring 2023.
Epic Research noted earlier work that showed rising self-pay encounters as Medicaid terminations resumed and that self-pay ED visits increased in months following the start of those terminations. With the unwinding now largely complete, the longer study window allowed researchers to assess whether early shifts persisted across multiple care settings and a broader time span.
The study used the Cosmos dataset, a large convenience sample drawn from Epic systems. The analysis included more than 550 million encounters and covered facilities in all 50 states plus Canada, Lebanon and Saudi Arabia. Researchers calculated quarterly payer shares in the four specified settings and used self-pay as a proxy for lack of insurance, acknowledging that the designation may also capture cash-pay arrangements or encounters with coverage not yet adjudicated.
Authors cautioned that part of the observed coverage-mix trends could reflect which health systems contributed data in any given quarter rather than changes in the underlying population. To reduce that risk, the analysis was restricted in some parts to departments that contributed data continuously across the full study period. The research was conducted independently by two teams who reached similar conclusions, according to Epic Research: one team included Kersten Bartelt, RN, and Eric Barkley; the other included Louis Kazaglis, MD, Grant Keane and Joe Deckert, PhD.
The report noted direct revenue-cycle implications for physician practices and hospitals. A rising share of self-pay encounters generally corresponds with lower collection rates and increased uncompensated care. That exposure is especially concerning for emergency department and inpatient services, where patients have limited ability to delay care and where the study saw the largest shifts toward self-pay.
The authors did not provide new estimates of dollar amounts of uncompensated care or specific impacts on collections; those details were not reported in the source article.
Epic Research’s findings describe payer-mix shifts through mid-2026 and relate them temporally to the Medicaid continuous-enrollment expiration and state-level unwinding that began in spring 2023. The study’s expanded timeframe was intended to determine whether earlier, short-term increases in self-pay persisted; the analysis suggests those shifts held across a broader span and multiple care settings.
Researchers reiterated methodological caveats — including the use of self-pay as a proxy for uninsurance and potential variation in contributing sites — and limited parts of the analysis to consistently reporting departments to help address those issues. The source did not report specific policy recommendations or projections beyond the observed coverage shares.
Between early 2022 and mid-2026, Epic Research found a clear upward trend in encounters billed as self-pay across emergency departments, inpatient admissions, births and primary care, accompanied by declines in Medicaid coverage shares in each setting. The trends were most pronounced in the ED and inpatient settings and were temporally associated with the end of the federal Medicaid continuous-enrollment provision and the subsequent state-level unwinding process.
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