title: Evidence for self-selection among health maintenance organization enrollees.
abstract: 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.
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D054598:Blue Cross Blue Shield Insurance Plans / Q000706:statistics & numerical data; D003256:Community Participation; D003365:Costs and Cost Analysis; D003657:Decision Making; D005251:Fees, Medical; D005260:Female; D006279:Health Maintenance Organizations / Q000191:economics / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota