Variations in nurse practitioner use in Veterans Affairs primary care practices

Background. Increasingly, primary care practices include nurse practitioners (NPs) in their staffing mix to contain costs and expand primary care. To achieve these aims in U.S. Department of Veterans Affairs medical centers (VAMCs), national policy endorsed involvement of NPs as primary care (PC) providers. Objectives. To evaluate the degree to which VAMCs incorporated NPs into PC practices between 1996 and 1999, and to identify the internal and external practice environment features associated with NP use. Study Design. We surveyed 131 PC directors of all VAMCs in 1996 and 1999 to ascertain the staffing and characteristics of the PC practice and parent organization (e.g., academic affiliation, level of physician staffing, use of managed care arrangements), and drew on previously published studies and HRSA State Health Workforce Profiles to characterize each practice's regional health care environment (e.g., geographic region, state NP practice laws, state managed care penetration). Using multivariate linear regression, we evaluate the contribution of these environmental and organizational factors on the number of NPs/10,000 PC patients in 1999, controlling for the rate of NP use in 1996. Principal Findings. From 1996-1999, NP use increased from 75 percent to 90 percent in VA PC practices. The mean number of NPs per practice increased by about 60 percent (2.0 versus 3.2; p<.001), while the rate of NPs/10,000 PC patients trended upward (2.2 versus 2.7; p=.09). Staffing of other primary care clinicians (e.g., physicians and physician assistants per practice) remained stable, while the NP-per-physician rate increased (0.2 versus 0.4; p<.001). After multivariate adjustment, greater reliance on managed-care-oriented provider education programs (p=.02), the presence of NP training programs (p=.05), and more specialty-trained physicians/10,000 PC patients (p=.09) were associated with greater NP involvement in primary care. Conclusions. Staffing models in VA PC practices have, in fact, changed, with NPs having a greater presence. However, we found substantial practice-based variations in their use, suggesting that more research is needed to better understand how they have been integrated into practice and what impact their involvement has had on the VA's ability to achieve its restructuring goals.