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

Horrocks S, Anderson E, Salisbury C

Authors' objectives

The objective was to compare care provided by nurse practitioners to patients at their first health service contact with care provided by doctors in primary care.


Recently published relevant journals, bibliographies and reference lists of reviews and papers were searched electronically and by hand. MEDLINE (from 1966 to 2001), EMBASE (from 1980 to 2001), CINAHL (from 1982 to 2001), the Science Citation Index, DARE, the National Research Register, the Cochrane Controlled Trials Register and the Cochrane EPOC Register of trials were searched for studies published in any language. Centres providing training for nurse practitioners in the UK, USA, South Africa and Australia were contacted for details of unpublished studies. The authors of identified studies were contacted for additional studies.

Study selection: study designs

Randomised controlled trials (RCTs) and prospective observational studies of experimental design with a concurrent control group were eligible for inclusion.

Study selection: specific interventions

Studies that compared care provided by nurse practitioners with similar care provided by doctors were eligible for inclusion. In the review, studies did not have to use the term 'nurse practitioner'. Studies were considered to be of nurse practitioners if care was provided at first contact with the patient, an initial assessment was made and the patients were managed autonomously. Studies in which nurses provided first point of contact care to unselected patients in any type of primary care (general practice, out-of-hours centres, walk-in centres, or emergency departments) were also included. The interventions had to take place in developed countries. Studies reporting single consultations and care provided over a period of time were included.

Study selection: participants

The review focused on undiagnosed patients with undifferentiated health problems. The included studies were located in family practice, paediatric clinics, medical centres, emergency departments, primary care and a prison clinic. The studies included patients with minor or recent injuries, families, patients requiring primary care after a visit to an emergency department, patients requesting urgent or same day appointments, children attending follow-up, patients with symptoms of upper respiratory tract infections or genitourinary symptoms, isolated North American Indian communities, and simulated patients.

Study selection: outcomes

Studies that assessed any of the following outcomes were eligible for inclusion: patient satisfaction, health status, health service costs, and process of care measures. The process of care outcomes that were assessed were consultation length, prescriptions, investigations, return consultation and referrals.

Study selection: how were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

Validity assessment

Validity was assessed using criteria described by the review group of the Cochrane EPOC Group. These validity criteria included: concealment of treatment allocation for RCTs or comparability of baseline characteristics for observational studies; follow-up greater than 80% for both nurses and doctors; objective measures or blinded assessment of the outcomes; outcomes assessed at baseline; use of reliable outcome measures; and allocation by practice or study location (see Web Address at end of abstract; accessed 04/04/2005). The authors did not state how the papers were assessed for validity, or how many reviewers performed the validity assessment.

Data extraction

Two reviewers independently extracted the data and resolved any disagreements through discussion with a third reviewer. The authors of studies with missing data were contacted.

Methods of synthesis: how were the studies combined?

The RCTs were combined in meta-analyses for patient satisfaction and individual process outcomes. A random-effects model was used. The pooled odds ratio (OR) and 95% confidence intervals (CIs) were calculated for dichotomous data, while the standardised mean difference (SMD) and 95% CIs were used for continuous data. RCTs reporting other outcomes were considered too heterogeneous for meta-analysis and narrative syntheses were undertaken. Observational studies were combined in a narrative.

Methods of synthesis: how were differences between studies investigated?

Statistical heterogeneity in the meta-analyses was tested for using the chi-squared statistic. Heterogeneity among RCTs reporting patient satisfaction was examined by comparing studies in different settings, comparing care provided at single consultations with care provided over a period of time, and by comparing studies of nurses with different levels of qualifications. Sensitivity analyses were performed by analysing data with and without studies in which the use of the term 'nurse practitioner' was doubtful.

Results of the review

Eleven RCTs (at least 80 nurse practitioners and 48 doctors treating around 14,000 patients) and 23 observational studies were included. Not all of the included studies reported the number of nurse practitioners and doctors.


Patient satisfaction (9 RCTs, 8 RCTs presented adequate data for meta-analysis): the 5 RCTs presenting continuous data showed that patients were more satisfied with nurse practitioners than doctors (SMD 0.27, 95% CI: 0.07, 0.47), but the studies were heterogeneous (P<0.00001). Heterogeneity remained after taking account of the level of nurse practitioner training and the number of consultations per patient (single versus care over time). All of the studies suggested increased satisfaction with nurses. The 3 RCTs presenting dichotomous data showed no significant difference between nurses and doctors in patient satisfaction (OR 1.56, 95% CI: 0.56, 4.34).

Health status (7 RCTs): heterogeneity in the measures and length of care precluded a meta-analysis. The studies showed no significant difference between care provided by a nurse or doctor.

Process measures: the studies showed that nurse consultations lasted significantly longer (5 RCTs; WMD 3.37 minutes, 95% CI: 2.05, 5.29; heterogeneity, P<0.00001) and that nurses undertook significantly more investigations than doctors (5 RCTs; OR 1.22, 95% CI: 1.02, 1.46; heterogeneity, P=0.18). The studies showed no significant difference for prescriptions (4 RCTs), return consultations (6 RCTs) or referrals (2 RCTs).

Quality of care (6 RCTs): heterogeneity in the measures precluded a meta-analysis. Nurse practitioners identified more physical abnormalities (1 RCT), gave more information to patients (1 RCT), kept more complete records and scored higher on communication (2 RCTs), and gave more advice on self-care and management (2 RCTs). Two RCTs showed no difference between nurse practitioners and doctors in the ordering and reporting of X-rays in emergency departments.

The authors reported that similar results were obtained from observational studies. Details of observational studies were reported as being available from the authors on request.

Cost information

Five studies presented information on the costs. The studies used different methods and were not adequately powered for an economic analysis.

Authors' conclusions

Nurse practitioners increased patient satisfaction, increased the length of the consultation, and performed more investigations than doctors. There was no difference between nurse practitioners and doctors in the health outcomes.

CRD commentary

The review question was clear in terms of the study design, intervention, participants and outcomes. Several relevant sources were searched, studies in any language were eligible for inclusion, and attempts were made to locate unpublished studies. The methods used to select the studies and assess validity were not described; hence, any efforts made to reduce errors and bias cannot be judged. More than one reviewer extracted the data, which reduces the potential for bias and errors. Supplementary tables included adequate information on the individual studies and results of the validity assessment.

Some of the data were combined in meta-analyses and statistical heterogeneity was assessed. Potential causes of heterogeneity were explored but significant heterogeneity remained for some outcomes, suggesting that meta-analysis might not have been an appropriate means of combining these studies. The authors discussed some of the limitations of the review. The evidence presented appears to support the authors' conclusions, but the unexplained heterogeneity indicates that results may not generalise to all setting and interventions.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that there is a need for further research. A large study with adequate follow-up is needed to compare nurse practitioners with doctors in the early detection of potentially serious illness, and there should be an economic assessment of substituting nurse practitioners for doctors. Future research should also address the following: factors leading to increased patient satisfaction rates for nurse practitioners; whether satisfaction rates for nurses and doctors are similar if both are working under similar conditions, such as similar consultation durations; the use of nurse practitioners with a wider range of patients, such as those with complex psychosocial problems or chronic disease; and the need to define what training, skills and experience nurse practitioners require.

Bibliographic detail

Horrocks S, Anderson E, Salisbury C. Systematic review of whether nurse practitioners working in primary care can provide equivalent care to doctors. BMJ 2002; 324: 819-823

Link to Pubmed record

URL for original research

Other publications of related interest

Full report available from:

This additional published commentary may also be of interest. Donald FC, McCurdy C. Review: nurse practitioner primary care improves patient satisfaction and quality of care with no difference in health outcomes. Evid Based Nurs 2002;5:121.

Subject index terms status

Subject indexing assigned by NLM

Subject index terms

Clinical Competence; Clinical Nursing Research; Nurse Practitioners /standards; Patient Satisfaction; Primary Health Care /manpower; Prospective Studies; Quality of Health Care; Randomized Controlled Trials as Topic

Accession number


Database entry date

30 April 2005

Record status

This record is a structured abstract written by CRD reviewers. The original has met a set of quality criteria. Since September 1996 abstracts have been sent to authors for comment. Additional factual information is incorporated into the record. Noted as [A:....].