Objectives: The aims of this study were to assess for changes in uninsured rates among trauma patients at age 64 versus 65 years and whether there are associated changes in post-discharge rehabilitation; determine whether changes are driven by rehabilitation provided at home, skilled nursing facilities (SNFs), or acute inpatient facilities; and determine whether changes vary among stratified subgroups of trauma-related "best-practice'' factors. Summary Background Data: Rehabilitation is an important component of high-quality trauma systems with access heavily influenced by insurance status. In the wake of policy changes affecting insurance coverage, it remains unknown the extent to which insurance changes associate with variations in rehabilitation access/use among otherwise similar patients. Methods: Regression discontinuity models were used to assess for changes in insurance status and rehabilitation at age 64 versus 65 years among adults ages 54 to 75 years (+/- 10 years age-related Medicare eligibility). Data were extracted from the 2007-2012 National Trauma Data Bank. Results: A total of 305,198 patients were included; 40.1% were discharged to rehabilitation. Medicare eligibility was associated with an abrupt 6.4 (95% confidence interval: 5.8-7.0) percentage-point decline in uninsured and a 9.6 (95% confidence interval: 6.5-12.6) percentage-point increase in rehabilitation at age 64 versus 65 years, enabling an additional 1-in-10 patients to access rehabilitation. Differences were driven by SNF use and were greatest among patients with less-severe clinical presentations. Restriction based on Medicare-payment eligibility to patients with length of stay >= 3days (SNF requirement) and >= 1 "presumptive diagnosis codes'' (inpatient facilities' 60% rule) demonstrated abrupt gains in both SNF and inpatient care. Conclusions: The results reveal the magnitude of changes in access to rehabilitation associated with changes in insurance coverage at age 65 years. Use of quasiexperimental models enabled meaningful consideration of health-policy change.