Spillover effects of the uninsured: local uninsurance rates and Medicare mortality from eight procedures and conditions.

The presence of a large uninsured population may create incentives to providers that affect the care delivered to all individuals in a health care market. Using Current Population Survey data on uninsurance rates and hospital discharge data on Medicare beneficiaries, this study investigates the relationship between the uninsurance rate at the metropolitan statistical area (MSA) level and inpatient quality of care delivered to Medicare beneficiaries, as measured by mortality from eight procedures and conditions. The results do not indicate large or widespread negative effects of the uninsured on Medicare beneficiaries. However, some evidence suggests that the relationship between the local uninsurance rate and Medicare mortality does vary by market size.