Evidence for self-selection among health maintenance organization enrollees
M. Jackson-Beeck and J. H. Kleinman
Inpatient utilization and health care costs of employees and their families
were studied for 11 employee groups covered by Blue Cross and Blue Shield
in the Minneapolis-St Paul area during the year before optional health
maintenance organization (HMO) enrollment. Before enrolling in HMOs, those
joining averaged 53% fewer inpatient days (470 days/1,000 v 994 days/1,000)
than those retaining fee-for-service (FFS) coverage. Both hospital and
professional expenditures were lower among HMO enrollees. Age-specific
analysis showed higher inpatient use of continuing FFS subscribers in every
category. Self-selection may be an important determinant of differences in
use and costs when comparing HMOs with FFS coverage.
