This review concluded that advanced practice registered nurses provided safe, effective and quality care in a variety of settings and in partnership with physicians and other providers had a significant role in the promotion of health. There were questions about data quality and some of the review methods but the relatively conservative conclusions appear reasonable.

To assess whether patient outcomes of care were similar with advanced practice registered nurses as with other providers.

PubMed and CINAHL were searched from 1990 to 2008. The search was limited to studies in English. ProQuest was searched.

Randomised controlled trials (RCTs) or observational studies conducted in USA between 1990 and 2008 with at least two groups of providers (advanced practice nurses working alone or part of a team and other individuals or teams without advanced practice nurses) and that reported quantitative outcomes on patient data were eligible for inclusion.

In the included studies advanced practice nurses included nurse practitioners, certified nurse midwives and clinical nurse specialists. Patient populations included adults and children with a wide variety of acute and chronic conditions and included generally low or low and moderate risk pregnant women in in-patient and community settings. The outcomes of interest were varied and included patient reported and clinical outcomes. Only outcomes that were reported in at least three studies were reported.

Two reviewers independently assessed studies for inclusion. Disagreements were resolved by consensus.

Quality was assessed and points were awarded according to similarity of participant groups, settings of groups, adequacy of sample size, validity and reliability of measures, control of bias and whether the outcome could be attributed to advanced practice nurses. The highest quality score was 8. Quality was reported as high quality (≥5) and low quality (<5).

Study quality was assessed by agreement of at least two reviewers. Disagreements were resolved by consensus.

Date were extracted in order to assess the study design, quality, numbers of studies reporting each outcome and direction of outcomes in each study.

Data was extracted by one reviewer and checked by a second. Disagreements were resolved by consensus and a third reviewer.

Data were summarised in a narrative discussion and grouped according to nurse classification and by outcomes and by collating information about the strength and quality of evidence according to the number, designs and quality of studies. Overall evidence gradings were classified as high, moderate, low or very low (full details reported).

Sixty-nine studies were included: 20 RCTs and 49 were observational studies. Eighteen RCTs were classified as high quality and two as low quality. Thirty-five observational studies were classed as high quality, 13 as low and one as high/low.

Thirty-seven studies compared nurse practitioner care groups to physicians (or teams without nurse practitioners). There were high levels of evidence for equivalent rates of patient satisfaction, self-reported perceived health, functional status, glucose control, blood pressure, emergency department visits, hospitalisation and mortality, and better serum lipid control. There were moderate levels of evidence for length of stay and low levels of evidence for duration of mechanical ventilation.

Twenty-one studies compared certified nurse-midwife managed care to physician managed care. There were high rates of evidence for nurse-midwife care being associated with lower rates of caesarian section, episiotomy, labour analgesia and third and fourth degree perineal lacerations. There were lower or comparable rates of vaginal operative deliveries and labour augmentation. There were equivalent rates of low birth weight and low Apgar scores and moderate levels of evidence for higher breastfeeding rates. There were comparable or higher rates of vaginal birth after caesarian, lower rates of epidurals and comparable or lower rates for neonatal intensive care admissions and labour induction.

Eleven studies assessed clinical nurse specialist care. Compared to controls there were high levels of evidence for equivalent rates of satisfaction and equivalent or lower length of stay and moderate levels of evidence for a decrease in complication rates.

Little data were available assessing certified registered nurse anaesthetists.

Four studies on clinical nurse specialist care reported on costs. There was a high level of evidence that clinical nurse specialist care reduced cost of care.

A high level of evidence indicated that advanced practice registered nurses provided safe, effective and quality care in a variety of settings and in partnership with physicians and other providers had a significant role in the promotion of health.

The aims of this review were clearly stated in terms of the inclusion criteria. It was unclear whether unpublished studies were sought so publication bias may have affected the review. The review methods appeared to be aimed at reducing possible reviewer error and bias. Study quality was assessed using an unpublished system and reported only as an overall rating of high or low quality; this made it difficult to comment independently on the reliability of evidence presented.

The decision to combine results in a narrative format appeared appropriate given the variety of studies included. Attempts were made to take study quality into consideration but collating outcomes on a vote-counting basis did not necessarily take into account differences between studies and in effect sizes. Much detail was presented about the included studies, including patient populations and settings, but there was no any indication of the size of any of the studies or length of follow-up. Many of the included studies were observational studies and the outcomes may have been open to influence from other confounding factors. This review was confined to nurses trained and working in the USA health care system and results may not necessarily be relevant to other systems.

Although there were questions about the quality of included data and some of the review methods, the relatively conservative conclusions appear reasonable.

Practice: The authors stated that USA heath care professionals needed to move forward with more collaborative models of care delivery.

Research: Te authors stated that research was needed to test models of care involving advanced practice registered nurses in additional settings and populations based on the needs of priority populations and health policy goals.

Tri-Council for Nursing, USA; Advanced Practice Registered Nurse Alliance, USA.

This is a systematic review that meets the criteria for inclusion on DARE. If you would like us to consider prioritising the writing of a critical abstract for this review please e-mail CRD-DARE@york.ac.uk quoting the Accession Number of this record. Please note that priority is given to fast track requests from the UK National Health Service.