Inpatient utilization by dual Medicare-Medicaid eligibles in Medicare risk HMOs and fee for service, California, 1991-1996.

Inpatient use among dual Medicare-Medicaid eligible beneficiaries in California Medicare HMOs and fee-for-service plans from 1991 to 1996 was compared, using a unique dataset that links Medicare enrollment data to inpatient discharge data. Dual eligibles in HMOs were found to have lower discharge rates, shorter lengths of stay, and fewer inpatient days than dual eligibles in the traditional fee-for-service system. Both, however, had higher discharge rates and inpatient days than non-dual-eligible beneficiaries. The results are consistent with previous findings documenting the high cost of dual eligibles, with the lower use in HMOs likely the result of differences in beneficiary characteristics and delivery of care between systems.