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Advanced Practice Registered Nurse Scope of Practice

Written by Dr. Ramon Martinez and Dr. Rieka Yu
Published on January 11, 2024
Research Highlights

Advanced practice registered nurses (APRNs) have advanced degrees and can practice midwifery, anesthesiology, or as a certified medical practitioner or specialist.

State laws determine which procedures APRNs may administer and where they can practice independent of a physician.

States that grant APRNs full practice authority have higher rural healthcare access, more prac-ticing APRNs and similar healthcare quality at a comparable cost.

APRNs provide medical services with varying levels of independence.

Health Professional Shortage Areas (HPSAs) are regions, groups, or institutions that lack sufficient access to primary medical care.

  • As of 2023, roughly 37% of the MO population lives in an HPSA (KFF 2023), the majority of which are rural and south of the Missouri River (MO DHSS 2020).
  • Nationwide, causes of HPSAs include an aging population and fewer specialized physicians (Regis College 2022).

APRNs in Missouri can act as primary care providers for acute, gynecological, and pain management care.

  • APRNs can provide 67-93% of primary care services, depending on the clinical setting (Maier 2016).
  • Approximately 15,500 APRNs are licensed to practice in Missouri (20% growth from 2021) (MO Board of Nursing 2024).
  • There are almost 2x as many APRNs per 100,000 residents in urban areas of MO than rural areas (MO Board of Nursing 2022).

APRNs in MO are subject to restricted practice laws that require them to collaborate with a physician to provide certain forms of care. Collaborating physicians must: (1) not collab-orate with more than six APRNs at a time, (2) be located within 75 miles from APRNs they super-vise, (3) review at least 10% of the APRNs’ health care charts and 20% of prescriptions of control-led substances every 14 days, and (4) supervise APRNs in-person for 1-month before allowing the APRN to practice independently or administer, dispense, or prescribe a controlled substance.

APRNs in MO can provide in-person services (without distance limits) in rural HPSAs up to 28 days per year. They can also provide rural telehealth indefinitely.


States with full practice authority for APRNs have increased healthcare access.

APRNs in 27 states and D.C. have full practice authority, meaning that they can independently diagnose, treat, and prescribe to patients with-out physician oversight (Figure 1) (AANP 2023).

States with full practice authority have more APRNs and healthcare delivery to rural (up to 5%↑) and low-income areas (up to 8% ↑), and HPSAs (up to 2% ↑) (Yang 2021; Poghosyan 2019; US DHHS 2015; Grumbach 2003).

  • Between 1998-2010, states with the fewest restrictions on APRNs had up to 2.5x more Medicare patients receive APRN care than states with more restrictions (Kuo 2013).
  • APRNs are more likely to be self-employed and work 3-4% more hours than nurses in states with more restrictive laws (Markowitz 2022; Kleiner 2016).
  • APRN service quality, including health outcomes and patient satisfaction, is comparable to physicians (Naylor 2010; Timmons 2016). However, there is limited data connecting full practice authority to improved patient outcomes (Ortiz 2018).
  • While the number of APRNs nearly doubled between 2010-2017, their increase is associated with a 3% loss of registered hospital nurses as they transitioned to advanced work (Auerbach 2020).
  • Between 2011-2018, full practice authority of APRNs decreased opioid prescriptions (by weight) by 2-7% (McMichael 2021).

Less restrictive APRN laws can increase the supply of APRNs to areas with low access to telehealth and transportation (MORH 2017). These laws do not increase the cost of physician care and, can lower costs for some services (Abraham 2019; Adams 2018).


Figure 1. Map of APRN scope of practice laws. Twenty-six states and Washington D.C. grant APRNs full practice authority (green), 13 states (yellow) limit at least one aspect of practice and 11 states (red), including MO, limit most aspects of APRN practice and require career-long supervision. Data from the American Association of Nurse Practitioners.


Changes to APRN laws have mixed results on the healthcare workforce.

Licensed APRNs in the US grew by 50% between 2008-2016. States with full practice authority have the highest number of APRNs, while the fastest percentage growth of licensed APRNs occurred in states with more restrictive scopes of practice (Barnes 2018).

  • APRNs are up to 5% more likely to practice in patient or primary care in states with full practice authority (US DHHS 2015).

Most studies only compare patient out-comes, quality and cost between states with full APRN authority and restricted practice laws.

  • Research on how moderate regulations (working hours, geographic proximity, or services provided) impact these outcomes is limited (McMichael 2022).

In 2013, 15 of 24 states (63%) with restrictive practice laws had APRN shortages, while 8 of 26 states (31%) with full practice authority had workforce shortages, suggesting other factors like reimbursement rates for services (85% for Medicaid patients), infrastructure for telehealth and electronic records, aging patient populations, and state residency requirements can also contribute to short-ages (US DHHS 2016).


2022 Missouri Nursing Workforce Report. (2022). Missouri State Board of Nursing Retrieved from https://pr.mo.gov/boards/nursing/2022%20Missouri%20Nursing%20Workforce%20Report.pdf 

Adams, E. K., & Markowitz, S. (2018). Improving efficiency in the health-care system: Removing anticompetitive barriers for advanced practice registered nurses and physician assistants. Policy Proposal, 8, 9-13.  

APRN Recognition Summary - State Of Missouri. (2023). Missouri Department of Professional Registration Retrieved from https://pr.mo.gov/boards/nursing/apnrecogsum.pdf 

Auerbach, D., Buerhaus, PI, Staiger, DO. (2020). Implications Of The Rapid Growth Of The Nurse Practitioner Workforce In The US. Health Affairs, 39(2), 273-279. doi:10.1377/hlthaff.2019.00686 

Barnes, H., Richards, MR, McHugh, MD, Martsoff, G. . (2018). Rural And Nonrural Primary Care Physician Practices Increasingly Rely On Nurse Practitioners. Health Affairs, 37(6), 908-914. doi:10.1377/hlthaff.2017.1158 

Grumbach, K., Hart, L. G., Mertz, E., Coffman, J., & Palazzo, L. (2003). Who is caring for the underserved? A comparison of primary care physicians and nonphysician clinicians in California and Washington. Annals of Family Medicine, 1(2), 97-104. doi:10.1370/afm.49 

Healthcare Delivery Sites in Rural Missouri. (2017). Missouri Department of Health and Senior Services Retrieved from https://health.mo.gov/living/families/ruralhealth/pdf/healthcare-delivery-sites-in-rural-missouri.pdf 

Impact of State Scope of Practice Laws and Other Factors on the Practice and Supply of Primary Care Nurse Practitioners (2015). U.S. Department of Health and Human Services Retrieved from https://aspe.hhs.gov/sites/default/files/private/pdf/167396/NP_SOP.pdf 

Kleiner, M. M., Marier, A., Park, K. W., & Wing, C. (2016). Relaxing Occupational Licensing Requirements: Analyzing Wages and Prices for a Medical Service. The Journal of Law and Economics, 59(2), 261-291. doi:10.1086/688093 

Kuo, Y. F., Loresto, F. L., Jr., Rounds, L. R., & Goodwin, J. S. (2013). States with the least restrictive regulations experienced the largest increase in patients seen by nurse practitioners. Health Affairs, 32(7), 1236-1243. doi:10.1377/hlthaff.2013.0072 

Maier, C. B., Barnes, H., Aiken, L. H., & Busse, R. (2016). Descriptive, cross-country analysis of the nurse practitioner workforce in six countries: size, growth, physician substitution potential. BMJ Open, 6(9), e011901. doi:10.1136/bmjopen-2016-011901 

Markowitz, S., & Adams, E. K. (2022). The Effects of State Scope of Practice Laws on the Labor Supply of Advanced Practice Registered Nurses. American Journal of Health Economics, 8(1), 65-98. doi:10.1086/716545 

Mcmichael, B. J. (2021). Nurse Practitioner Scope-of-Practice Laws and Opioid Prescribing. The Milbank Quarterly, 99(3), 721-745. doi:https://doi.org/10.1111/1468-0009.12524 

Missouri Primary Care Needs Assessment (PCNA) 2020. (2020). Missouri Department of Health and Senior Services Retrieved from https://health.mo.gov/living/families/primarycare/pdf/primary-care-needs-assessment-2020.pdf 

Naylor, M. D., & Kurtzman, E. T. (2010). The role of nurse practitioners in reinventing primary care. Health Affairs, 29(5), 893-899. doi:10.1377/hlthaff.2010.0440 

Nurse Practitioners and the Primary Care Shortage. (2023). Retrieved from https://onlinenursing.regiscollege.edu/resources/mha/infographics/nurse-practitioners-and-the-primary-care-shortage/ 

Ortiz, J., Hofler, R., Bushy, A., Lin, Y. L., Khanijahani, A., & Bitney, A. (2018). Impact of Nurse Practitioner Practice Regulations on Rural Population Health Outcomes. Healthcare (Basel, Switzerland), 6(2). doi:10.3390/healthcare6020065 

Poghosyan, L., Timmons, E. J., Abraham, C. M., & Martsolf, G. R. (2019). The Economic Impact of the Expansion of Nurse Practitioner Scope of Practice for Medicaid. Journal of Nursing Regulation, 10(1), 15-20. doi:10.1016/S2155-8256(19)30078-X 

Primary Care Health Professional Shortage Areas (HPSAs). (2023). Retrieved from https://www.kff.org/other/state-indicator/primary-care-health-professional-shortage-areas-hpsas/?activeTab=map&currentTimeframe=0&selectedDistributions=total-primary-care-hpsa-designations&sortModel=%7B%22colId%22:%22Location%22,%22sort%22:%22asc%22%7D 

State-Level Projections of Supply and Demand for Primary Care Practitioners: 2013-2025. (2016). U.S. Department of Health and Human Services Retrieved from https://bhw.hrsa.gov/sites/default/files/bureau-health-workforce/data-research/primary-care-state-projections2013-2025.pdf 

State Practice Environment. (2022). Retrieved from https://www.aanp.org/advocacy/state/state-practice-environment 

Timmons, E. J. (2017). The effects of expanded nurse practitioner and physician assistant scope of practice on the cost of Medicaid patient care. Health Policy, 121(2), 189-196. doi:10.1016/j.healthpol.2016.12.002 

Yang, B. K., Johantgen, M. E., Trinkoff, A. M., Idzik, S. R., Wince, J., & Tomlinson, C. (2021). State Nurse Practitioner Practice Regulations and U.S. Health Care Delivery Outcomes: A Systematic Review. Medical Care Research and Review, 78(3), 183-196. doi:10.1177/1077558719901216 


**This Note has been updated since its original publication. Previous versions are not up-to-date, but can be accessed here: Version 1 (December 2020), Version 2 (December 2021), Version 3 (January 2023).

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