Nurse practitioners can provide care that leads to increased patient satisfaction and similar health outcomes when compared with care from a doctor. Nurse practitioners seemed to provide a quality of care that is at least as good, and in some ways better, than doctors.
Although all of the randomised trials found no significant differences between doctors and nurse practitioners in health outcomes, the research has important limitations. The studies used many different outcome measures, reflecting the difficulty in measuring changes in health outcomes after single consultations predominantly about minor illnesses. None of the studies in our review was adequately powered to detect rare but serious adverse outcomes. Since one important function of primary care is to detect potentially serious illness at an early stage, a large study with adequate length of follow up is now justified.
Limitations of the review
Ambiguity exists over the use of the term “nurse practitioner,” with much debate about this role.22,23
The overlap between nursing roles in the United Kingdom and the introduction of another advanced practice nursing title, nurse consultant, adds to the difficulty in understanding the role definitions in nursing.1,2,24
Although specific training for nurse practitioners is available, the content of this varies.25
Because of this ambiguity, the definition used in our review was purposefully inclusive.
Our review was limited by the quality of the available studies. There were few recent randomised trials, and the larger number of observational studies were generally of poor quality. Because of these problems we based our conclusions primarily on the randomised trials, the more recent of which were of generally high quality, although only one study used patients new to both providers.14
Noticeable heterogeneity was observed between the studies on almost all outcomes. Although differences between studies in terms of setting, level of nurse training, and the period of time studied were anticipated and explored in our review, much heterogeneity remained after allowing for these factors. This probably reflects the diverse ways in which nurse practitioners currently work. Despite these differences, the direction of the effect for the main findings was consistent between different studies and also between the randomised controlled trials and the observational studies.
It was not possible to conduct a robust economic analysis of the costs of care from nurse practitioners compared with doctors. Only five studies provided data about costs.10,12,15,16,26
These used different approaches to the valuing of resources and were inadequately powered for economic analysis. The lack of good evidence about the economic impact of substituting nurse practitioners for doctors needs to be addressed in future research, otherwise changes may be introduced that are thought to be efficient when they may not be so.27
Our review lends support to an increased involvement of nurse practitioners in primary care. However, most recent research has been based on nurse practitioners providing care for patients requesting same day appointments predominantly for acute minor illness and working in a team supported by doctors. It cannot be assumed that similar results would be obtained by nurse practitioners working in different settings or with different groups of patients, nor that they could substitute entirely for general practitioners.
Future research should address several unresolved issues. Firstly, if patients are more satisfied with care provided by nurse practitioners then the factors that lead to this effect should be elucidated. Satisfaction with care could be related to differences in the training and consultation skills of nurses, patients' expectations, or the extra length of time that nurse practitioners spend in consultations.
Secondly, nurse practitioners and doctors did not necessarily work under similar circumstances or with similar pressures on their time, even in the controlled trials. It is necessary to determine whether the differences between nurse practitioners and doctors in patient satisfaction and quality of care remain if they work under identical circumstances, particularly with the same rates of booked consultations.
Thirdly, research on nurse practitioners needs to be broadened to encompass a wider range of patient groups, including those with complex psychosocial problems or chronic diseases. Research is also necessary that extends beyond the scope of comparing individual nurses with doctors and evaluates different models of organisation, such as several nurse practitioners providing care at first point of contact supported by a smaller number of general practitioners providing second line advice.
Finally, the role of a nurse practitioner is not clearly defined in the United Kingdom and includes nurses from a wide range of educational backgrounds. In addition, nurses are increasingly involved in assessing and advising patients with minor illness in settings such as NHS Direct and NHS walk-in centres without a recognised qualification for this role. It is important to study the training, skills, and experience that nurses need in order to offer the benefits to patients shown by our review.
Patients are at least as satisfied with care at the point of first contact with nurse practitioners as they are with that from doctors. Although assessments of the quality of care and short term health outcomes seem to be equivalent to that of doctors, further research is needed to confirm that nurse practitioner care is safe in terms of detecting rare but important health problems.