Nurse practitioners and physician assistants as primary care providers in institutional settings.

This paper describes the scope of primary care practice and autonomy of nurse practitioners (NPs) and physician assistants (PAs) at nine health maintenance organizations (HMOs) and multispecialty clinics (MSCs). We found that the larger an institution's managed care population, the greater the NPs' and PAs' scope of practice and autonomy, although patients with complex illnesses or multisystem problems usually were referred directly to a physician. Alternative policies to increase the number of primary care physicians might slow the growth in hiring new NPs and PAs, but are unlikely to reduce their primary care role in managed care settings. Further research is needed to consider whether these results are applicable to a broader range of practice settings.