Association of Insurance Payor with Time to Discharge to Inpatient Rehabilitation After Ischemic Stroke

Background: Transition timing to post-acute rehabilitation after ischemic stroke is heavily influenced by non-clinical factors, introducing potential systemic disparities in care access. We evaluated the association between insurance payor status and acute hospital length of stay (LOS) prior to inpatient rehabilitation discharge among critically ill stroke patients. Methods: Using the MIMIC-IV database, we identified ICU-admitted adults with ischemic stroke discharged to inpatient rehabilitation (n=1,285). The primary outcome was hospital LOS prior to rehab transfer. Multivariable log-transformed linear regression evaluated the association with insurance payor (Medicare, private, other/unknown; reference: Medicaid), adjusting for demographics, diagnostic-code counts (medical complexity), and ICU LOS (acute illness severity). Results: Median hospital LOS before rehab discharge was longest for Medicaid patients (13.2 days) compared with private insurance (11.0 days) and Medicare (9.5 days). In the adjusted model, Medicare insurance was associated with a significantly shorter transition time to inpatient rehabilitation, corresponding to a 13.5% shorter acute hospital stay (adjusted LOS ratio 0.87; 95% CI: 0.79-0.96; p=0.005) relative to Medicaid. Private insurance demonstrated a descriptive trend toward shorter LOS that did not achieve statistical significance (adjusted LOS ratio 0.93; 95% CI: 0.84-1.02; p=0.122). Other and unknown payor categories showed no significant differences. Conclusions: Insurance payor status serves as an independent predictor of acute care transition timing for stroke patients requiring inpatient rehabilitation. The prolonged acute stays observed among Medicaid beneficiaries suggest significant non-clinical, administrative bottlenecks in post-acute placement, underscoring the critical need for standardized, streamlined insurance approval pathways to ensure equitable neurological recovery.