The Quality and Effectiveness of Care Provided by Nurse Practitioners

Abstract and Introduction

Abstract

Evidence regarding the impact of nurse practitioners (NPs) compared to physicians (MDs) on health care quality, safety, and effectiveness was systematically reviewed. Data from 37 of 27,993 articles published from 1990–2009 were summarized into 11 aggregated outcomes. Outcomes for NPs compared to MDs (or teams without NPs) are comparable or better for all 11 outcomes reviewed. A high level of evidence indicated better serum lipid levels in patients cared for by NPs in primary care settings. A high level of evidence also indicated that patient outcomes on satisfaction with care, health status, functional status, number of emergency department visits and hospitalizations, blood glucose, blood pressure, and mortality are similar for NPs and MDs.

Introduction

The inter-related concepts of health care access, cost, and quality are central to the ongoing health policy debate in the United States. Specific issues include the decreased number of primary care physicians,^[1–3] escalating costs for chronic disease management,^[4] and the quality of care delivered.^[5] In health care, definitions of quality continue to evolve. The Institute of Medicine defined quality in 1990 as the "degree to which health services for individuals and populations increase the likelihood of attaining desired health outcomes and are consistent with current professional knowledge."^[6]

Quality of care includes both clinical and experiential aspects of care viewed from the patient's perspective.^[7] Safety and effectiveness further define quality. Safe care is unlikely to injure or harm the patient.^[8] Safety is also characterized as the "freedom from accidental or preventable injuries produced by medical care."^[9] Effective care is both based on scientific evidence and produces the intended result.^[10] In addition, the IOM asserts that, in order for care to be considered high quality, it should also be patient-centered, timely, efficient, and equitable.^[8]

These characteristics clearly link patient preferences and care processes with quality.^[6] Donabedian, the father of health care quality, suggested that care quality could be improved by establishing standards for care structures and processes.^[11] Patient outcomes become the ultimate measures of quality as they reflect the influence of both structures and processes of care.^[7,11,12,13]

Since nurse practitioner (NP) training programs were created nearly 50 years ago, NPs have assumed increasing responsibilities as providers in the health care system. Over the past 5 years, groups from many political frames of reference have suggested that NPs should play even greater roles and be granted full practice authority.^[14–18] At this critical time, we need to know to what extent NPs contribute to the quality, safety, and effectiveness of health care. Without further information in this area, it is difficult to determine how to best integrate NPs to improve access to health care or which models of care achieve the highest quality. These knowledge gaps must be filled when the health care needs of society are so great.

Over the past 35 years, several reviews and meta-analyses have sought to assess what is known about NP practice.^[19–27] Results indicate that care involving NPs, compared with care without them, is associated with better outcomes in terms of blood pressure^[20,21,27] and blood glucose control^[27] and for hospital length of stay (LOS).^[26] Outcomes are similar^[19,25,26] or better^[21–23,27] in terms of patient satisfaction and symptom management.^{[19–21,25,26,27]} Patient health status,^[22,23,26] functional status,^[21,26,27] use of the emergency department (ED),^[23,27] and hospitalizations^[23,26] are also similar among patients cared for by NPs or by other providers.

While previous systematic reviews and meta-analyses provide some insights into NP effects on specific outcomes, they are dated, restrict their analysis to primary care settings, or include studies in a variety of countries where NP educational background and practice parameters differ widely. A comprehensive review of the scientific literature on the care provided by NPs in the US is needed to inform educational, organizational, and health policy. By filling that need, the review reported here strengthens and extends the conclusions drawn from previous reviews. It does so by including studies published over the past 18 years that examine US NPs exclusively, examining outcomes of care provided to any patient population and in any setting, and without restricting patient outcomes reported.

The purpose of this systematic review was to answer the following question: How do NPs affect patient outcomes on measures of care quality, safety, and effectiveness? The study is part of a larger systematic review of the outcomes from the 4 advanced practice nurse (APN) groups: NPs, clinical nurse specialists, certified nurse-midwives, and certified registered nurse anesthetists.^[28,29] For the larger study, the research question was intentionally broad to encompass as many outcomes as possible: "How do APNs affect the safety, quality, and effectiveness of care?" Readers who are interested can find the results from the larger systematic review described in more detail in the main review report.^[28,29] This article's focus on NP outcomes provides greater depth of description of the NP studies reviewed (patient populations, practice characteristics, measures used, etc) and integrates findings from this work with existing evidence on NP outcomes.

Journal for Nurse Practitioners. 2013;9(8):492-500.e13. © 2013 Elsevier Science, Inc.