Characteristics of patient visits to nurse practitioners and physician assistants in hospital outpatient departments.

Many authors have described differences between nurse practitioners and physician assistants. Most studies have compared physician with nonphysician providers' practice. Few studies have compared nurse practitioners and physician assistants, and none has used a national data base. This exploratory, atheoretical research examined which of the following characteristics predicted patients being seen by nurse practitioners and physician assistants: patient and hospital demographics, diagnosis, diagnostic/screening services, therapeutic services, and disposition of the visit. The data set used for analysis was the 1992 National Hospital Ambulatory Medical Care Survey. Based on a multistage probability design yielding national estimates for patient visits in hospital outpatient settings, the National Hospital Ambulatory Medical Care Survey showed that there were 2,847 weighted patient visits to either nurse practitioners or physician assistants (4.6 million patient visits using national estimates). Results of multivariate logistic regression suggest that nurse practitioners were the most likely nonphysician provider for outpatients receiving more health promotion and counseling (therapeutic) services and for those needing women's and children's services. Outpatients in rural areas predicted visits to physician assistants. As more nonphysician providers enter the work force, the results of this research may assist with understanding the utilization of nurse practitioners and physician assistants in primary care.