Patterns of health maintenance organization service areas in rural counties.

This study analyzes the 1993 National Directory of HMOs to determine the extent to which rural counties are included in health maintenance organization (HMO) service areas. Two specific questions are addressed: (1) How do the patterns of service areas differ across HMO model types? (2) What are the characteristics that distinguish rural counties served by HMOs from those that are not? Although a majority of rural counties are in HMO service areas, substantially fewer are served by non-individual practice association (non-IPA) models. Access to HMO services is found to decrease with county population density, and adjacency to metropolitan areas is an important predictor of inclusion in service areas.