Inpatient utilization by undocumented immigrants without insurance.

Data collected from a large county hospital in Miami, Florida were used to study the severity of illness (using the Case Mix Severity Index) and resource use (measured by average length of stay, procedures, and/or diagnostic tests performed) of undocumented persons from Dade Country, Florida in an inpatient setting. Compared with native-born populations and those with permanent residency status (insured by Medicaid or of uninsured status) admitted to the same hospital, undocumented immigrants had a higher Case Mix Severity Index but a lower adjusted average length of stay. Undocumented immigrants and uninsured residents of the United States had a similar number of adjusted procedures/ tests performed, but less than Medicaid beneficiaries. Policy issues are discussed.