Are nurse practitioners (NPs) and physician assistants (PAs) the same and therefore substitutable? It is an interesting question posed in “Specialty distribution of physician assistants and nurse practitioners in North Carolina,” by Fraher and colleagues on page 38.
I have a somewhat unique perspective on this question given that I am an NP and a PA. Let's take a closer look.
Despite the variability in workforce models that predict shortages or maldistribution of various types of healthcare providers, the general consensus is that demand for healthcare services will continue to grow as a result of the Affordable Care Act, the aging population, and increased prevalence of chronic disease.1,2 Additionally, new models of interdisciplinary care require the expertise and flexibility that NPs and PAs provide.3 PAs and NPs will play important roles in addressing these emerging healthcare needs.1-3
The two professions enjoy significant areas of overlap, yet are still distinct in their education, initial certification, maintenance of certification, and licensure. Both PAs and NPs are educated through programs that include didactic and clinical coursework. NP programs are based on the nursing model and are at the graduate level (master's or doctorate).4 PA programs are based on the medical model, and more than 98% of PA programs are at the master's level.5
Finally, although differing in their specific language, the competencies for the PA and NP professions have similar foundations in core knowledge in the health sciences, accountability for professional practice, effective individual and team communication, advocacy for patients and the profession, quality/practice improvement, and systems-based practice.6,7 However, a striking difference is the specific NP core competency of “...functions as a licensed independent practitioner.”7 This competency is consistent with the Consensus Model for APRN Regulation, but very different from the PA competency to “...partner with supervising physicians....”6,8 PA and NP education, licensure, and scope of practice are summarized in Table 1.
These differences account, in part, for the differences in employment trends we see between the two professions.1,9,10 At the entry-to-practice level, PA education prepares generalist clinicians who are ready to practice medicine in collaboration with a physician. The physician-PA team relationship is a foundational aspect of the PA profession.12,13 Upon graduation, a PA is an adaptable provider. Akin to a stem cell, the PA has the flexibility to move into any specialty practiced by a supervising physician. And unique among healthcare providers at this level of practice, the PA retains this flexibility. Almost 50% of PAs practice in more than one specialty over the course of their careers, and of these, 20% practice in three or more specialties.9
NP education and scope of practice is a complex subject. The Consensus Model for APRN Regulation: Licensure, Accreditation, Certification, & Education (the “LACE” model) was developed to address the lack of a uniform model for APRN regulation, including that of NPs, across the United States.8 Introduced in 2008, the LACE model has been successful in standardizing education, accreditation, and certification for NPs. However, no uniform model of regulation (licensure) of NPs exists across the United States.15 NP scope of practice is regulated by each state and varies widely. State regulations range from independent practice in which NPs have full practice authority under the exclusive licensure authority of the state board of nursing to restricted practice requiring supervision, delegation, or team-management by an outside health discipline.16 Implementation of the LACE model and the resultant improvement of consistency and standardization of NP education across the United States has increased NP mobility from state to state. However, it has decreased NP career flexibility in population-focused scope of practice.17 NP academic preparation is focused on the direct care of patients either in primary care or acute care. The educational focus is further classified according to one of six population foci: family/individual across the lifespan, adult-gerontology, neonatal, pediatrics, women's health/sex-related, or psychiatric-mental health. Additional specialties are defined by specific healthcare needs of the population.8 The role and population focus are the basis for national certification and licensure. However, a key point is that a specialty cannot expand the scope of practice of an NP beyond that of the role and population of the initial education and certification. For example, a primary care family NP who takes a continuing-education course in adult critical care does not change her or his scope of practice to become an acute care adult NP. Likewise, a pediatric NP who completes a continuing-education course in care of older adults does not add to his or her scope of practice to become an adult-gerontology NP, and thus certified to care for all ages.8 Similarly, a general internist physician who attends a continuing-education course on orthopedic surgery does not become an orthopedic surgeon.
In order to change population focus and thus become certified in a new scope of practice, an NP must complete additional formal education. This additional education is most commonly in the form of a postgraduate (post-master's or postdoctoral) certificate program in the new area of specialization.8 Consistent with a foundation in the nursing model, more than 80% of NPs are educated and certified in primary care specialties (family, adult, gerontology, women's health, or pediatrics). Most (54.5%) are educated and certified as family NPs (FNPs).10 Among NP roles, the FNP role provides the most flexibility with regard to providing services across the lifespan.
Within each population scope of practice, NPs can and do subspecialize. About 57% of NPs report practicing in at least one subspecialty, with cardiovascular (8.3%) and emergency (7.3%) as the top two subspecialties reported nationally.10 This mirrors the trends found by Fraher and colleagues.1 Therefore, although career flexibility of NPs is limited by the population-focused scope of practice, NPs still retain some flexibility in subspecialization within each population focus.
When we consider the interchangeability of PAs and NPs in healthcare settings, we must consider outcomes of care as well as role flexibility. Multiple studies examining patient outcomes in both primary care and acute care settings demonstrated equal or improved outcomes where care was provided by PAs or NPs versus physicians.18-22 And there are a few studies in critical care settings that compare care delivered by both PAs and NPs to that of physicians.23,24
Interestingly, little research directly compares PA and NP practice outcomes. One observational study compared the quality of diabetes care provided by PAs, NPs, and physicians in family medicine practices; and found that practices with NPs were more likely to monitor target diagnostic tests, treat hyperlipidemia, and have patients achieve target lipid levels.25 However, data were insufficient to draw conclusions regarding the performance of PAs versus NPs.
In day-to-day practice, the quality of care provided by NPs—whether primary care or acute care—is indistinguishable from care delivered by PAs (or physicians). However, PA education and practice are based on the medical model. NP education and practice, grounded in the nursing model, will always be recognizable by its emphasis on health promotion, disease prevention, and health education. Therefore, in response to the question, “Are PAs and NPs interchangeable?” my answer is, “No.” Each profession brings a different conceptual framework, and thus a different focus, to practice. However, the question truly goes beyond the question raised by Fraher and colleagues. The question to be asked is, “How do we create a robust system of care in which our patients reap the benefit of access to an interdisciplinary team in which both the nursing and medical models are represented?” Each profession has unique background, education, and perspective that differentiate them from each other and from physicians. Embracing the diversity of PAs and NPs enhances healthcare.
1. Fraher EP, Morgan P, Johnson A. Specialty distribution of physician assistants and nurse practitioners in North Carolina. JAAPA
2. Bodenheimer T, Chen E, Bennett HD. Confronting the growing burden of chronic disease: can the U.S. health care workforce do the job. Health Aff (Millwood)
3. Hooker RS, Brock DM, Cook ML. Characteristics of nurse practitioners and physician assistants in the United States. J Am Assoc Nurse Pract
6. Accreditation Review Commission on Education for the Physician Assistant, National Commission on Certification of Physician Assistants, Physician Assistant Education Association, American Academy of Physician Assistants. Competencies for the physician assistant profession. https://www.aapa.org/WorkArea/DownloadAsset.aspx?id=2178
. Accessed January 26, 2016.
8. Hooker RS, Cawley JF, Leinweber W. Career flexibility of physician assistants and the potential for more primary care. Health Aff (Millwood)
9. American Association of Nurse Practitioners. 2013-14 National Nurse Practitioner Practice Site Census. 2015. American Association of Nurse Practitioners; 2015.
13. Mitchell RE. Evaluating the clinical preparation of physician assistant versus nurse practitioner students and the characteristics of their preceptors. Internet J Academic Physician Assistants
17. Rounds LR, Zych JJ, Mallary LL. The consensus model for regulation of APRNs: implications for nurse practitioners. J Am Assoc Nurse Pract
18. Mundinger MO, Kane RL, Lenz ER, et al. Primary care outcomes in patients treated by nurse practitioners or physicians: a randomized trial. JAMA
19. Horrocks S, Anderson E, Salisbury C. Systematic review of whether nurse practitioners working in primary care can provide equivalent care to doctors. BMJ
20. Newhouse RP, Stanik-Hutt J, White KM, et al. Advanced practice nurse outcomes 1990-2008: a systematic review. Nurs Econ
21. Kawar E, DiGiovine B. MICU care delivered by PAs versus residents: do PAs measure up. JAAPA
22. Oswanski MF, Sharma OP, Raj SS. Comparative review of use of physician assistants in a level I trauma center. Am Surg
23. Gershengorn HB, Wunsch H, Wahab R, et al. Impact of nonphysician staffing on outcomes in a medical ICU. Chest
24. Gershengorn H, Wunsch H, Wahab R, et al. Outcomes in the medical intensive care unit: a physician-extender/attending paradigm works as well as the traditional housestaff model. Relationship between ICU structures/processes and outcomes [abstract]. Am J Respir Crit Care Med
25. Ohman-Strickland PA, Orzano AJ, Hudson SV, et al. Quality of diabetes care in family medicine practices: influence of nurse-practitioners and physician's assistants. Ann Fam Med