Changes in the Lifetime Experience of Health Insurance in the US

Importance The US uninsured rate hit a historic low in 2023, but point-in-time rates reveal little about how US residents experience insurance over their lifetimes. Understanding whether declines in uninsured rates were driven by fewer coverage losses, shorter uninsured periods, or both is important as Medicaid and Marketplace eligibility rules change. Objective To estimate how the lifetime experience of US health insurance changed across eras. Design, Setting, and Participants A health insurance simulation model was calibrated to project lifetime insurance occupancy and transitions for synthetic US birth cohorts followed through the pre-Medicare years. Age-specific transition rates were estimated from longitudinal Medical Expenditure Panel Survey data and calibrated to American Community Survey estimates; mortality was derived from US life tables and income-specific data. Uncertainty intervals (UIs) were derived from 1000 calibration posterior draws. Exposures Insurance transition and mortality dynamics drawn from 3 eras: 2009-2010, 2018-2019, and 2022-2023. Main Outcomes and Measures Expected total years with employer-sponsored, nongroup private, public, and no insurance; coverage-loss events; mean uninsured period duration. Results Expected lifetime years uninsured in the noninstitutionalized population declined from 10.98 years (2009-2010; 95% UI, 10.95-11.03 years) to 6.76 years (2018-2019; 95% UI, 6.72-6.80 years); a change of −4.73 years (95% UI, −4.79 to −4.70 years). Among people below 200% of the federal poverty level, the decline was from 19.85 years (2009-2010; 95% UI, 19.81-19.90 years) to 11.68 years (2018-2019; 95% UI, 11.64-11.71 years); a change of −8.18 years (95% UI, −8.24 to −8.13 years). Both declines were offset mainly by gains in public coverage. Mean uninsured period duration increased in the noninstitutionalized population (3.42 to 3.84 years) but fell in the low-income subcohort (4.56 to 3.94 years). Decomposition attributed the overall decline in uninsured years to slower coverage losses; among the low-income group, the decline was attributed to fewer coverage losses and faster reentry into coverage once uninsured. Conclusions and Relevance In this study, expected lifetime exposure to uninsurance before Medicare eligibility declined between 2009-2010 and 2022-2023, especially among people with a low income. Coverage loss remains a vulnerability that resolves faster but is not prevented.