Serving distinct populations: performance in Medicaid HMOs and commercial HMOs

The objective of this study was to compare the preventable emergency department (ED) admissions of Medicaid health maintenance organization (HMO) beneficiaries and commercial HMO beneficiaries in the state of Florida, in addition to analyzing the effect of HMO market conditions in relation to these admissions. Paired and unpaired t tests and 10 regression equations were estimated using ED hospital admission data to examine the differences between Medicaid and commercial HMOs in 5 commonly recognized preventable hospitalization conditions. For the same preventable ED admissions, Medicaid and commercial HMO beneficiaries had statistically different rates of admission. In 3 of 5 conditions, Medicaid HMO beneficiaries had more preventable ED admissions than did commercial HMOs for the same conditions. HMO market conditions did not have a statistically significant association with preventable ED admissions for either beneficiary group, whereas teaching status and the percentage of females admitted to the hospital under a given HMO payer type had the greatest effect on preventable ED admissions. Whereas uncontrolled comparisons of preventable ED admissions are statistically different between Medicaid and commercial HMO beneficiaries, controlling for hospital and patient characteristics, market conditions do not affect the rate of preventable ED admissions.