Clinical Research Study
Nurse Practitioners, Physician Assistants, and Physicians Are Comparable in Managing the First Five Years of Diabetes

https://doi.org/10.1016/j.amjmed.2017.08.026Get rights and content

Abstract

Background

Increasing use of nurse practitioners and physician assistants is a possible solution to the shortage of primary care providers in the United States, but the quality of care they provide is not well understood.

Methods

Because the scope of practice of the 3 provider types is similar in the Veterans Health Administration, we determined whether patients managed by primary care nurse practitioners, physician assistants, or physicians had similar hemoglobin A1c levels at comparable times in the natural history of diabetes. Our retrospective cohort study examined veterans with newly diagnosed diabetes in 2008, continuous primary care from 2008 to 2012, and more than 75% of primary care visits with nurse practitioner, physician assistant, or physician.

Results

Of the 19,238 patients, 95.3% were male, 77.7% were white, and they had a mean age 68.5 years; 14.7%, 7.1%, and 78.2% of patients were managed by nurse practitioners, physician assistants, and physicians, respectively. Median hemoglobin A1c was comparable at diagnosis (6.6%, 6.7%, 6.7%, P > .05) and after 4 years (all 6.5%, P > .5). Hemoglobin A1c levels at initiation of the first (7.5%-7.6%) and second (8.0%-8.2%) oral medications for patients of nurse practitioners and physician assistants compared with that of physicians was also similar after adjusting for patient characteristics (all P > .05). Nurse practitioners started insulin at a lower hemoglobin A1c (9.4%) than physicians (9.7%), which remained significant after adjustment (P < .05).

Conclusions

At diagnosis and during 4 years of follow-up, diabetes management by nurse practitioners and physician assistants was comparable to management by physicians. The Veterans Health Administration model for roles of nurse practitioners and physician assistants may be broadly useful to help meet the demand for primary care providers in the United States.

Introduction

Diabetes is a major health problem in the United States. More than 29 million Americans have diabetes, with 1.4 million newly diagnosed in 2013.1 In 2012, the American Diabetes Association estimated that the total economic burden of diagnosed diabetes in the United States was $176 billion in direct costs.2

After enactment of the Affordable Care Act, more Americans obtained access to health care. However, less than one third of physicians in the United States currently practice in a primary care specialty.3 One study estimated that the United States requires an additional 46,000 primary care providers by 2025 to meet patient demands.4 The shortfall in primary care providers has spurred interest in the role of nurse practitioners and physician assistants in the primary care management of chronic diseases such as diabetes. Although the cost of using nurse practitioners and physician assistants is lower than physicians,5 whether nurse practitioners, physician assistants, and physicians deliver similar quality of care is poorly understood.

Several studies have suggested that patients managed by nurse practitioners and physician assistants have outcomes similar to those of physicians.6, 7, 8, 9, 10, 11 However, because of the scope of practice laws,3, 12 only a few studies included direct comparisons between nurse practitioners or physician assistants and physicians with similar independence and patient populations. Comparisons of diabetes care in particular have mainly been limited to cross-sectional analyses of single hemoglobin A1c levels without comparisons at similar time points in the natural history of the disease.9, 13

We chose the Veterans Health Administration (VHA) as a model health care system in which to compare diabetes outcomes between patients managed by primary care nurse practitioners, physician assistants, and physicians. Of the approximately 8.3 million patients seen at the Veterans Affairs each year,14 an estimated 1 in 5 has a diagnosis of diabetes.15 The VHA is the largest integrated health care system, as well as the largest employer of nurse practitioners and physician assistants in the nation.16, 17 The majority of nurse practitioners and physician assistants in the VHA primary care setting are responsible for patient panels similar to those of physicians, and can prescribe noncontrolled medications, place orders, and document without physician co-signatures.18 In 2005 to 2010, up to 29% of VHA primary care provider visits in 2010 were attended solely by nurse practitioners and physician assistants, with diabetes being the third most common primary care visit diagnosis for physicians and nurse practitioners, and fourth among physician assistants.18

Our study used the national VHA Corporate Data Warehouse database to compare nurse practitioners, physician assistant, and physician management of patients with diabetes who were at comparable stages of their natural history—at diagnosis in 2008, during 4 years of follow-up, and at initiation of oral medications and insulin.

Section snippets

Study Design

We conducted a retrospective analysis to compare hemoglobin A1c levels in patients managed by primary care nurse practitioners, physician assistants, or physicians. All patients were newly diagnosed with diabetes in 2008, had 4 years of consistent primary care follow-up, and had annual hemoglobin A1c levels documented through 2012. This study was approved by the Emory University Institutional Review Board and the Atlanta Veterans Affairs Research and Development Committee.

Database

The Corporate Data

Diabetes Cohort

In 2008, 19,238 veterans had 2 years of primary care before a new diagnosis of diabetes, continuity of primary care from 2006 to 2012, a hemoglobin A1c at diagnosis and at least 1 hemoglobin A1c per year from 2008 to 2012, and a majority of visits with a single provider type (Supplementary Figure 1, available online). Of these, 2,821 were managed by nurse practitioners, 1,367 were managed by physician assistants, and 15,050 were managed by physicians. Concordance between visit provider type and

Discussion

The results of our study demonstrate that primary care nurse practitioners and physician assistants provide glycemic management that is comparable to that of physicians for patients who had newly diagnosed diabetes with 4 years of follow-up. There was no difference in hemoglobin A1c levels at diagnosis, initiation of the first and second oral medications, or after 4 years of primary care follow-up among nurse practitioners, physician assistants, or physicians, after adjusting for patient

Conclusions

From a health quality and policy standpoint, our results demonstrate that independently practicing nurse practitioners and physician assistants, within a highly integrated health care system, are able to perform as well as physicians in the management of diabetes at diagnosis and during 4 years of follow-up care. These findings indicate that there could be benefits from expanding the roles of nurse practitioners and physician assistants in patient management both within and outside of the

Acknowledgments

The authors thank Christine Jasien, Atlanta Veterans Affairs Medical Center, who assisted the authors with obtaining Veterans Affairs Informatics and Computing Infrastructure data. The authors also thank Qing He, Emory School of Public Health, for assistance with data analysis.

References (29)

  • S. Horrocks et al.

    Systematic review of whether nurse practitioners working in primary care can provide equivalent care to doctors

    BMJ

    (2002)
  • M.O. Mundinger et al.

    Primary care outcomes in patients treated by nurse practitioners or physicians: a randomized trial

    JAMA

    (2000)
  • A.W. Kamps et al.

    Outpatient management of childhood asthma by paediatrician or asthma nurse: randomised controlled study with one year follow up

    Thorax

    (2003)
  • Y.F. Kuo et al.

    Diabetes mellitus care provided by nurse practitioners vs primary care physicians

    J Am Geriatr Soc

    (2015)
  • Cited by (42)

    • Endocrine Edition March 2023

      2023, Journal for Nurse Practitioners
    • Access and Delivery of Adult Congenital Heart Disease Care in the United States: Quality-Driven Team-Based Care

      2020, Cardiology Clinics
      Citation Excerpt :

      Although there are significant training differences between NPs, who train in an advanced nursing model, and PAs, who train in the medical model, their roles within health care frequently are indistinguishable. As a group, under the umbrella term APP, they have proved themselves high-quality providers who deliver excellent care and increase access to care, while decreasing overall health care costs.16–19 Based on this evidence, academic medical centers across the United States have embraced APPs as a way to increase access to care, with a median utilization of 1 APP to every 5 physicians.20

    View all citing articles on Scopus

    Funding: MKR, AT, DO, and LSP are supported in part by the Veterans Affairs. This work is not intended to reflect the official opinion of the Veterans Affairs or the US government.

    This work was supported in part by FDA award RO1FD003527 (L.S.P), VA awards HSR&D IIR 07-138 (L.S.P, S.L.J.), and I01-CX001025 and I01-01BX003340 (L.S.P.), NIH awards R21DK099716 (L.S.P., Q.L., and S.L.J.), DK066204 (L.S.P.), U01 DK091958 (L.S.P. and M.K.R.), U01 DK098246 (L.S.P. and D.E.O.), R21 NS091630 (Q.L.), and a Cystic Fibrosis Foundation award PHILLI12A0 (L.S.P). The sponsors had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.

    Conflicts of Interest: The authors declare that there is potential duality of interest associated with this manuscript. With regard to potential conflicts of interest, within the past 5 years, LSP has served on the Scientific Advisory Boards for Boehringer Ingelheim, Profil, and Janssen, and has or had research support from Merck, Amylin, Eli Lilly, Novo Nordisk, Sanofi, PhaseBio, Roche, AbbVie, GlaxoSmithKline, Janssen, Vascular Pharmaceuticals, GlaxoSmithKline, AstraZeneca Pfizer, and the Cystic Fibrosis Foundation. In the past, he was a speaker for Novartis and Merck, but not for the last 5 years. DO has research support from Novo Nordisk and Amylin, and QL receives support from the National Institutes of Health, Patient-Centered Outcomes Research Institute, National Science Foundation, American Health Association, and the Cystic Fibrosis Foundation and served as a consultant for Eisai. SLJ received support from Amylin. These activities involve diabetes, but have nothing to do with this article. After the study reported here was completed, LSP founded a company, Diasyst Inc, which aims to develop and commercialize diabetes management programs. Other authors have no potential conflicts of interest to declare.

    Authorship: All authors had access to the data and played a role in writing this manuscript.

    This work was presented in part at: the American Diabetes Association meeting, June 13-17, 2014, San Francisco, California.

    View full text