Patient Outcomes from Care Provided by Advanced Practice Nurses in the U.S.

Sunday, 27 July 2014: 8:30 AM

Julie A. Stanik-Hutt, PhD, CRNP, CNS, FAAN
Department of Acute and Chronic Care, Johns Hopkins University, School of Nursing, Baltimore, MD
Kathleen M. White, PhD, RN, NEA-BC, FAAN
Dept of Acute and Chronic Care, Johns Hopkins University, School of Nursing, Baltimore, MD


Background: Advanced practice nurses (APNs) are registered nurses who have completed post -graduate education that prepares them for advanced and expanded practice as a nurse practitioner [NP], nurse midwife [CNMs], nurse anesthetist [CRNAs], or a clinical nurse specialist [CNS].Issues related to access, cost and quality are at the core of ongoing discussions regarding health care. With the growing need for highly qualified health care providers, the best available evidence should be used to make decisions regarding how best to utilize the skills of APNs.  Data is needed by educators, governmental officials and employers so they can create appropriate educational programs to prepare APNs, policies which authorize optimal APN practice and delivery models that utilize each health care professional’s skills to the fullest.  A systematic review of all available research which uses systematic and explicit methods to identify, select and critically appraise evidence and then aggregate that evidence, is needed to support these decisions.


Purpose: To synthesize and critically apprise the body of knowledge produced by randomized controlled trials (RCT) and observational comparative (OC) studies which examine patient outcomes derived from care provided by APNs.  


Data Sources: An exhaustive search of the published and unpublished research literature from 1990 – 2008 was completed. A variety of databases including the Cumulative Index to Nursing and Allied Health Literature, Pub Med, Proquest, the Cochrane Database as well as others were searched.  Governmental reports and grants, and dissertations were included. Manuscript references and footnotes were also hand searched. 

Study Selection: A methodical process was used to select studies to include in this review. Two reviewers independently reviewed first the title, then the abstract, and finally the article to determine whether it met inclusion criteria.  At the title level only one reviewer had to determine the article should be included, there after both reviewers had to determine that the article met inclusion criteria.  The TrialStat System (SRS v4, Ottawa, ON) was used to store retrieved studies, conduct the title and abstract reviews, and document decisions.  Articles which reported on patient outcomes related to quality, effectiveness or safety of care by an APN, whether from an RCT or OC study which compared patient outcomes from an APN provider group to those from a provider group without an APN were included. All studies had to be completed in the United States.


Data Extraction, Appraisal and Synthesis: 27,993 titles were reviewed and ultimately yielded 109 studies which met all criteria for inclusion (NP, 49; CNS, 24; CNM, 23; CRNA, 4; and CNS and NP combined, 9). Data on patient outcomes were extracted from each study and used to create detailed evidence tables stratified by APN type. Evidence tables also included information on study characteristics (provider types, setting of care, patient characteristics, sample size, etc.).  Studies were critically appraised for quality using a modified Jadad Scale (> 5 = high quality, < 4 = low quality) and that score was added to the data table. Outcomes from individual studies were then aggregated. For an outcome to be reported, at least three studies had to report data for the outcome.  Because not all outcomes met this criteria, data from only 75 of the 109 studies could be aggregated (NP, 37; CNS, 13; CNM, 21; CRNA, 0; and CNS and NP combined, 4). Aggregated data on each outcome was appraised for quality a second time using the GRADE Working Group Criteria. The GRADE criteria assessed the quality, quantity and consistency of the data. It had been hoped that outcomes could also be pooled from across studies in order to complete a meta-analysis, however limitations in reporting the literature prevented same.

 Conclusions: 30 abstracted outcomes from 75 of the 109 studies reviewed (22 randomized controlled trials and 53 observational) were aggregated and contributed to the conclusions.  70 % of the patient outcomes (21 of 30) were supported by a high level of overall evidence.


Nurse Practitioners: Patient outcomes from care by NPs or by physicians (MDs) supported  1) a high level of evidence of similar patient outcomes regardless of provider for: patient satisfaction with provider/care, self-report of perceived health status, functional status, blood glucose, blood pressure, emergency department visits, hospitalization, and mortality; 2) a high level of evidence that NP management of serum lipids produced better patient outcomes than those from management by a physician; and 3) a moderate level of evidence that LOS and a low level of evidence that patient duration of ventilation is similar among patients cared for by either provider type.

Clinical Nurse Specialist:  Patient outcomes from care involving a CNS or without a CNS supported, 1) a high level of evidence that CNS involvement decreases hospital LOS and costs; 2) a high level of evidence that patient satisfaction is not affected by a CNS; 3) a moderate level of evidence that a CNS reduces complications; and 4) a low level of evidence that patient’s perception of quality of life are affected by a CNS.


Certified Nurse Midwives: When patient outcomes from CNMs are compared to those from MDs, a high level of evidence shows that 1) numbers of low birth weight infants and Apgar scores are similar; and 2) CNM care reduces the rate of episiotomy and perineal laceration, use of labor analgesia or labor augmentation, vaginal operative delivery and Cesarean section.  A moderate level of evidence indicates that 3) mothers managed by a CNMs are more likely to breastfeed their baby; 4) admission to neonatal intensive care unit after CNM delivery is no more likely than after MD delivery; and 5) lower use of epidural analgesia and labor induction, as well as vaginal birth after Cesarean.  Differences between CNM and MD outcomes are particularly evident for so called ‘overused’ interventions (Cesarean section, labor induction/augmentation, epidural anesthesia, forceps and vacuum use, episiotomy, and labor analgesia).