Evidence Brief: The Quality of Care Provided by Advanced Practice Nurses [Internet]

Washington (DC): Department of Veterans Affairs (US); 2014 Sep.


The term “Advanced Practice Registered Nurse” (APRN) encompasses the Nurse Practitioner (NP), Certified Registered Nurse Anesthetist (CRNA), Clinical Nurse Specialist (CNS), and Nurse Midwife (NM).

Today, most NPs practice in primary care. Autonomy or independence has always been central to the concept of a nurse practitioner as a primary care provider. The National Council of State Boards of Nursing defines “independence” as practicing with “no requirement for a written collaborative agreement, no supervision, [and] no conditions for practice.” Although the authority to diagnose and prescribe are the most frequently mentioned aspects of independence, the concept encompasses other dimensions including entry into practice; authority to bill for services independently; access to diagnostic services and hospital admitting privileges; and recognition as primary care providers.

Medical licensing is a state function and APRN scope-of-practice (SOP) laws vary from state to state. In 16 states, APRNs have the authority to practice without a written agreement with a supervising physician, 9 states require physician involvement to prescribe but not to diagnose and treat, and in 24 states physician oversight is required to prescribe, diagnose, and treat. The definition of “oversight,” however, varies by state, and most states allow collaboration or supervision to occur remotely. There is also variation in SOP laws regarding APRNs' authority to supervise clinical staff. For example, one article notes a requirement in sections 2069–71 of the California Business and Professions Code that doctors and selected other professions— but not registered nurses—may supervise California medical assistants.

While there is disagreement about whether APRNs should practice independently, the seemingly arbitrary variation in SOP laws among the states is nearly universally criticized. As an editorial from the Commonwealth Fund put it, “objectively interpreted data on the competencies of professionals should guide policy, not rigid, often antiquated state laws.”

The National Governors Association and the Institute of Medicine (IOM) have criticized variation in SOP regulations among the states, and both argue that nurses should be able to practice to the “full extent of their education and training” in order to adapt to the changing health care system after the implementation of the Affordable Care Act (ACA), which authorizes nurse-managed health clinics and other innovations. In March, 2014, a report from the Federal Trade Commission, relying in large part on the IOM report, argued that physician supervision or collaborative practice agreement requirements “may sometimes restrict competition unnecessarily, which can be detrimental to health care consumers and have broader public health consequence,” that is, “decreased access to health care services, higher health care costs, reduced quality of care, and less innovation in health care delivery.” In the context of the ACA, one emergent issue is whether some patient care teams should be led by a nurse practitioner instead of only a medical doctor. Other advocates for change argue that, nationally, removing restrictions on NP practice would improve access to primary care and allow NPs to emerge as leaders of the integrated teams that are an important component of new models for delivering primary care.,,

THE IMPACT OF STATE SOP REGULATION: Despite the strong statements from multiple groups, there has been very little formal study of the impact of SOP laws on access to and quality of care. The National Governors Association report, supporting the elimination of most SOP restrictions for APRNs, notes:

More restrictive SOP rules are probably associated with slower growth in the number of NPs and in the number of Medicare patients cared for by NPs. In both 2006 and 2010, the odds of having an NP as a primary care provider were 2.5 times higher in the least restrictive states compared to the most restrictive states. These findings have not been directly associated with overall access to primary care, and it is unclear whether SOP rules exert this effect directly, or indirectly via the policies of state and private payers. In an extensive provider survey, “at the point of care, scope-of-practice laws were not found to have substantial impact across the study states on what services NPs can deliver, despite significant differences across states in the level of NP autonomy…” Rather, the study found that payer policies had more impact than SOP laws on how and where NPs can practice. Payers in states with restrictive SOP laws often add additional restrictions, such as not recognizing NPs as primary care providers, that make independent NP practice difficult. In addition, Medicare policies do not permit a NP to order home health care or durable medical equipment, even in states in which NPs practice independently.

Other arguments made by advocates for APRNs about the adverse effects of SOP restrictions are based on hypothetical reasoning or on anecdotes concerning inefficient use of time and, in some cases, delay in needed care because a physician's approval was required to prescribe, order equipment, or admit a patient to the hospital.

PHYSICIAN GROUP PERSPECTIVES: Physician groups that support SOP restrictions envision a system in which physicians delegate the care of less complex patients to (supervised) nurse practitioners; one physician advocacy group has estimated that “nurse practitioners and physician assistants are capable of providing 70% or more of the care required for adults and 90% in pediatrics.” According to J.K. Iglehart, the AMA supports team-based care but argues that teams should be led by medical doctors, as integrated systems such as Geisinger, Kaiser Permanente, and the VA have done.

These groups also argue that physicians may be better able to manage complicated diagnostic problems, patients with multiple chronic conditions, and unstable patients. These claims are plausible—as Blumenthal and Abrams note, “[p]hysicians and nurse practitioners receive very different training, and it would be surprising if their competencies were identical.” However, no studies have been done to examine the validity of these beliefs.

Physician groups also argue that policymakers should take into account that patients prefer having a medical doctor as a primary care provider and that use of the title “doctor” by APRNs who have completed doctoral training could confuse patients about the training of their provider. Evidence about patients' preferences regarding the type of provider is conflicting.

VETERANS HEALTH ADMINISTRATION PRACTICE ENVIRONMENT AND PREVIOUS RESEARCH: In the Veterans Health Administration (VHA), the use of APRNs in the delivery of health care, including primary, specialty, acute, and home health care, expanded greatly after the implementation of the Veterans Integrated Service Network (VISN) structure in October 1995 and the Veterans Health Care Eligibility Reform Act in 1996 (Public Law 104-262). These changes resulted in a shift to local and regional networks grounded in ambulatory and primary care, an increase in the number of patients served by the VHA, and an increase in the percentage of patients seeking primary care services: 20% in fiscal year 1994 to 76% in fiscal year 1996. In 1996, 75% of VHA primary care practices reported using NPs and by 1999, this proportion had risen to 90%. Today the VHA employs over 4,700 nurse practitioner full time equivalents, 786 CRNAs, and 482 CNSs.

Currently, although a single unrestricted license allows APRNs to work at any VA facility, the VHA observes state-by-state rules regarding prescribing and admission privileges and physician supervision for APRNs. Each VA institution establishes its own policies regarding all other aspects of scope of practice. Advocates for “federal supremacy” argue that overriding state laws would “increase access to health care services, reduce costs and improve the quality and availability of health care” for Veterans by eliminating bureaucratic complexity and “artificial barriers” such as supervisory requirements., They note that varying regulations for diagnosing and prescribing can delay appropriate care and waste time and resources, particularly for CNSs in cardiology and other specialties working in VA facilities that serve patients from more than one state.

Research on APRNs in the VHA has been sporadic, and has focused on NPs rather than CRNAs or CNSs. From 1995 to 1999, the VHA HSR&D conducted one single-center RCT and several observational studies of the impact of NPs on access to specialty care, continuity of care, and resource use.- Some studies demonstrated improved continuity of and access to care after implementation of an interdisciplinary firm system,- however, little research was conducted in the 2000s., The best recent data are from a 2011 cross-sectional study of all VISN 11 primary care patients who had hypertension and/or diabetes. VISN 11 includes 2 states (Illinois, Michigan) with very restrictive scope of practice laws and 2 states (Ohio, Indiana) with moderately restrictive laws. The main findings were:

  1. On average, primary care NPs cared for less complicated patients than primary care physicians. MDs were caring for the more complex patients within the study sites.

  2. Provider type was not significantly associated with an elevated blood pressure or creatinine level in either diabetic or hypertensive patients nor with an elevated HbA1c in diabetics.

  3. Increased use of resources by NPs was not demonstrated. NPs were less likely than physicians to obtain psychiatric referrals.

A survey of VISN 11 NPs and MD providers was also part of this study. The main findings were:

  1. Over 80% of NPs said they assess acutely ill/unstable patients on their own, and about 70% said they also plan care and make medication changes on their own.

  2. VHA NPs and physicians reported a high degree of collegiality.

  3. Nevertheless, there were “striking differences” between physicians' and nurses' beliefs about the NPs' scope of practice. About 50% of physicians (vs 21% of NPs) were apprehensive about the fact that NPs function on their own, particularly for acute/unstable patients.

A 2012 ESP report reviewed the evidence on the role of primary care providers' skill level (MD vs NP/PA) in ambulatory care settings in influencing patient outcomes from a VHA perspective. The authors of the ESP report stated that they “did not review studies that examined the effect of skill levels on patient quality of care or patient safety as it is widely accepted that medical school or more training increases quality of care.” The best evidence the ESP identified came from 2 randomized controlled trials which consistently found no difference in patient satisfaction with provider interaction when seeing a NP/PA instead of an MD. The ESP report also noted that a large VA study of patient satisfaction among 1.6 million veterans seen in 21 VISNs provided some limited information about impact of skill level: patient satisfaction increased in 3 VISNs that hired more NP/PAs.

USE OF EVIDENCE IN POLICY DEBATES: In a policy paper, Newhouse and colleagues state “[o]nce the issue of comparability between APRN care and that delivered by physicians is set aside in favor of an integrated team concept, disciplines can focus on…overarching goals” such as developing patient-centered team care, reducing quality gaps, and educating an interprofessional workforce. Their recent systematic review of RCTs and observational studies supports the emphasis on team care outlined in their policy paper. Including all types of APRNs, intermediate and health outcomes, and various patient populations and settings, Newhouse et al concluded that the outcomes of care provided by APRNs in collaboration with specialist or primary care physicians are similar to, or in some cases better than, the outcomes of care provided by a physician alone.

Although Newhouse et al's emphasis on the role of APRNs in integrated teams is more relevant to the current organization of primary care services in VHA, policy discussions about over-riding state SOP laws invoke the argument that APRNs working independently provide the same quality of care as medical doctors.,, The Institute of Medicine, for example, claims that a large body of evidence “does not support the conclusion that APRNs are less able than physicians to provide safe, effective, and efficient care.” Similarly, a publication from the Robert Wood Johnson Foundation (RWJF) asserts that “health outcomes are comparable for patients treated by primary care NPs and MDs.”

Most articles about the role of APRNs do not explicitly define the autonomy of the nurses, compare non-autonomous nurses with physicians, or evaluate nurse-direct protocol-driven care for patients with specific conditions. However, studies like these are often cited in support of the claim that APRNs practicing autonomously provide the same quality of primary care as medical doctors. For example, the RWJF publication quoted above refers to a review by Naylor and Kurtzman that relied on 2 systematic reviews published in 2002 and 2005, and 2additional randomized trials published in 2009. Many of the trials included in 2 older systematic reviews were considered by Naylor and Kurtzman.,

The first additional trial comparing NP and general physician care was conducted 2 months after the NPs successfully completed a Masters-level training program. As nurses were not permitted to prescribe independently, physicians were “always available for consultation and to validate prescriptions and referrals.” The second randomized trial included in the Naylor and Kurtzman review evaluated a 4-visit, computer-guided, nurse-led intervention for overweight and obese patients conducted in 11 general practice (GP) locations.

Most research on APRNs has evaluated team models of care or interventions designed to enhance care for patients with specific conditions (eg, incontinence, bronchiectasis, heart failure, etc.).,,, The evidence supporting the contributions of APRNs in team models of care, protocol-driven care and nurse-led intervention focusing on a specific patient population is relevant to VHA and reasonably up-to-date., VA-ESP recently published a report that concluded there is strong evidence that nurse-managed protocols help to improve health outcomes among patients with moderate severity of diabetes, hypertension, hyperlipidemia, and chronic heart failure.

Nevertheless, the issue of the comparability of health outcomes of autonomous APRNs and physicians continues to be a cornerstone of the debate regarding state SOP rules. Because no previous systematic review has focused on this issue, the VHA Office of Quality, Safety and Value commissioned the VA Evidence-based Synthesis Program (ESP) Coordinating Center to reevaluate recent, original studies that reported health outcomes.

Publication types

  • Review