Nurse practitioners (NPs) are Advanced Practice Registered Nurses who have additional responsibilities for administering patient care as compared to Registered Nurses (RNs).1 The concept NPs originated in the United States.2,3 To date, many countries that have developed NPs-related talent training. To be a NP, one needs to go through the following 3 steps: Step 1, become a practicing RN and take a minimum of 2 years to complete the master of nursing (MSN) program, which is a necessary condition to be an NP.4 Step 2, continue to maintain the NP license and earn the BSN (Bachelor in Nursing Science) degree. If you have already earned a Bachelor of Nursing, you can skip “step 2,” fortunately. Step 3, earn the advanced practice nursing licensure in practical nursing through exam and certification requirements. Individuals successfully satisfying these requirements would work as an NP in hospitals, nursing homes, and other health-care or medical facilities, after completing the steps outlined above. Nonetheless, some NPs choose to take a step back from hands-on patient care to pursue managerial or administrative positions.1,5 NPs include General NP, Certified Registered Nurse Anesthetist, Gerontological NP, Psychiatric NP, and Family NP. In the United States, NPs provide high-quality care in rural, urban, and suburban communities, and in many scenarios, including clinics, hospitals, emergency rooms, urgent care sites, private physicians or NP practices, nursing homes, schools, colleges, and public health departments. NPs provide the following services: (1) diagnosing and treating acute and chronic conditions; (2) managing patients’ overall care; (3) educating patients on disease prevention and positive health and lifestyle choices; and (4) prescribing medications and other treatments. The specialty areas include (1) acute care, (2) adult health, (3) family health, (4) gerontology health, (5) neonatal health, (6) oncology, (7) pediatric/child health, (8) psychiatric/mental health and (9) women's health (American Association of Nurse Practitioners 2012–2019). The origin of the NPs role in Canada lies in the work of nurses who, decades ago, provided care in rural and remote areas.6 They provide comprehensive health assessment, diagnose, treat, and manage acute and chronic diseases.
The Canadian NPs consisted of practitioners, consultants/collaborators, leaders, and researchers, and they may also work collaboratively with interprofessional teams, other health-care providers, and community members.7 Canadian Nurse Association6,8 has mentioned that they have developed the RN Prescribing Framework which has been compiled based on the NP's experience of practicing and other countries implementing RN prescribing are supported by country, provinces, and regions.8 In Australia, after finishing their program, RNs will become NPs.9,10 In accordance with Australian Nursing and Midwifery Council Policy, NPs should obey the following standards: NP (1) assesses using diagnostic capability, (2) plans care and engages others (3) prescribes and implements therapeutic interventions, and (4) evaluates outcomes and improves practice.9 According to an Israeli study, as NPs do have a positive impact on the overall health of patients, there is a strong willingness to integrate nurses into healthcare.11 However, NPs have an emerging role in development in China, even though there are some achievements about NPs in Taiwan and Hong Kong, few hospitals in the mainland have started to try NPs. The concept, courses setup, education, role function, registration, and certification of NPs are not been exactly defined.12,13 To summarize, NPs of various countries around the world are as professional as they are in developing health-care delivery. Therefore, there is an increasing number of literature reports in this field, and so more and more relevant literature need to be continuously searched and read by relevant researchers. The purpose of the study is to comb the current situation and trends of NPs and analyze the relevant literature in the Web of Science Core Collection (WoSCC) database using CiteSpaceV software.
The data of this bibliometric study came from the WoSCC database, which includes Science Citation Index Expanded, Social Sciences Citation Index, and Arts and Humanities Citation Index.
To explore the trends in NPs, we retrieved NPs-related studies published from 1986 to 2018 (as literature cannot be fully covered until 2019) in the WoSCC database. The index topics included “Nurse Practitioners,” “Nursing,” “Nurses,” “Practical,” and “Private Duty.” And the retrieval strategy is as follows: TS = (“Practical” and “Nurses”) OR (“Practical” and “Nursing Care”) OR “Nursing, Private Duty” OR “Nursing, Practical,” OR “Nurse Practitioners.” All studies were retrieved and downloaded on June 20, 2019. Simultaneously, the “fully documented and cited references” of literature were exported in the “other file formats” using the format of “plain text”. The types of documents downloaded are “review” and “articles” and no language-related restrictions were applied to the search. All the searched records were exported to CiteSpaceV software for further analysis, and then all results were organized using Excel 2016.
Not only the bibliometric analysis but also the visualization of literature is used widely to analyze the relevant research data in many research fields, such as psycho-metric, nanotechnology, aviation engineering, economic geography, ecological security and science, strategic management, and technology policy analysis.14 However, the bibliometric analysis about nurses, especially the NPs, still produced only sparse results. In order to explore more about the development tendency and hotspots in this field, the CiteSpaceV software has been used in the visualization related to NPs. CiteSpaceV is a software used in literature metrology. Using it, we can identify the literature and information visualization in many knowledge domains. It was developed by the team of Chaomei Chen of Drexel University, US, using Java program.15 The CiteSpaceV is inspired by Thomas Kuhn's structure of scientific revolutions that centers on the change of research focus over time, sometimes incrementally or rapidly. Recently, CiteSpaceV has also been used in medicine sometimes. However, the nursing-related articles are relatively few. There were only 546 published papers16, 17, 18 that were related to clinical nursing, nursing education, palliative care, and midwifery.
Based on what has been analyzed above, we made a bibliometric analysis of the literature on NPs using CiteSpaceV. Many visual items were used in our study, for example, (1) the analysis of citation and co-citation can help us to detect hot-topics in the field which we focus on; (2) although this metric—which can be found in every project—is burst, it is a normal one; however, it is very important to do a burst detection algorithm to identify emergent research-front concepts, reference and authors, and so on;19 (3) centrality is an important index of visual analysis, which can be used to measure and highlight the potential pivotal points in some research fields;20 (4) in addition, through the analysis of author, country, and institutions, we can detect the one that is the pivotal-point, and that will be provided as the reference for us to get cooperation. The results of our study are as follows.
The initial search identified 4912 entries, including 4547 articles (92.57%) and 365 reviews (7.43%). Furthermore, it contains 15 languages, such as English (4802, 97.76%), German (30, 0.61%), and Portuguese (16, 0.33%); and English has the highest entries. Out of the 4912 studies, the first article on NPs was published in Belgium by De Becker21 in 2007 in a series of books, which are entitled
In this section, we analyzed the publication and citation frequency of authors and list the top 10, as shown in Table 1. As we can see, the high-productive author is Gardner G (24, 0.49%) in this research field according to the number of papers. In addition, the strength of the burst of Gardner G (burst 5.26, 2015–2018) ranked second among the top 10 authors
Publication and citation frequency of the top 10 productive authors.
No. | Author | Publications counts | Proportion of publications (%) | Citation freq | Citation freq (per paper) | Burst | Centrality |
---|---|---|---|---|---|---|---|
1 | Gardner G | 24 | 0.49 | 464 | 19.33 | 5.26 | 0 |
2 | Gardner A | 21 | 0.43 | 381 | 18.14 | – | 0 |
3 | Hooker RS | 20 | 0.41 | 205 | 10.25 | 4.54 | 0 |
4 | Cashin A | 16 | 0.33 | 134 | 8.38 | – | 0 |
5 | Donald F | 15 | 0.31 | 195 | 13.00 | 5.08 | 0 |
6 | Hornor G | 15 | 0.31 | 137 | 9.13 | – | 0 |
7 | Martin-Misener R | 15 | 0.31 | 229 | 15.27 | 5.44 | 0 |
8 | Poghosyan L | 14 | 0.29 | 76 | 5.43 | – | 0 |
9 | Freed GL | 13 | 0.26 | 130 | 10.00 | – | 0 |
10 | Kilpatrick K | 13 | 0.26 | 166 | 12.77 | 4.91 | 0 |
If, in an article, 2 or more authors are from the same institute or country, it is referred to as cooperation. In this section, we will analyze the institutes and countries of the authors of these studies. Judging cooperation based on the co-occurrence frequency of institutions and countries, we found the top 10 institutions and countries. First, we must remember that the size of the circle indicates the number of papers published by institutions and countries. The thickness of links represents the linking strength between institutions or between countries. As we can see, the University of Michigan (90, 1.83%) is the most productive one among the 4557 institutions and the University of California, San Francisco (88, 1.79%) comes second
Publication and citation frequency of the top 10 productive institutions.
Ranking | Institution | Publication count | Proportion of publications (%) | Citation freq | Citations (per paper) | Centrality |
---|---|---|---|---|---|---|
1 | University of Michigan | 90 | 1.83 | 785 | 8.72 | 0.12 |
2 | University of California San Francisco | 88 | 1.79 | 1854 | 21.07 | 0.07 |
3 | Duke University | 83 | 1.69 | 863 | 10.40 | 0.03 |
4 | University of Washington | 81 | 1.65 | 881 | 10.88 | 0.19 |
5 | University of Pennsylvania | 75 | 1.53 | 1123 | 14.97 | 0.06 |
6 | University of North Carolina | 73 | 1.49 | 856 | 11.73 | 0.03 |
7 | University of TORONTO | 73 | 1.49 | 1178 | 16.14 | 0.17 |
8 | Columbia University | 68 | 1.38 | 786 | 11.56 | 0.29 |
9 | Johns Hopkins University | 66 | 1.34 | 903 | 13.68 | 0.03 |
10 | University of Pittsburgh | 64 | 1.30 | 626 | 9.78 | 0.04 |
Publication and citation frequency of the top 10 productive countries and regions.
Ranking | Country | Publication count | Proportion of publications (%) | Citation freq | Citations (per paper) | Centrality |
---|---|---|---|---|---|---|
1 | USA | 2737 | 55.72 | 26229 | 9.58 | 0.35 |
2 | England | 398 | 8.10 | 4714 | 11.84 | 0.35 |
3 | Canada | 369 | 7.51 | 4579 | 12.41 | 0.09 |
4 | Australia | 356 | 7.25 | 3688 | 10.36 | 0.05 |
5 | Netherlands | 222 | 4.52 | 3174 | 14.30 | 0.11 |
6 | Sweden | 113 | 2.30 | 1182 | 10.46 | 0.05 |
7 | Germany | 112 | 2.28 | 914 | 8.16 | 0.04 |
8 | Scotland | 79 | 1.61 | 1019 | 12.90 | 0.08 |
9 | Taiwan, China | 73 | 1.49 | 626 | 8.58 | 0 |
10 | Peoples Republic China | 71 | 1.45 | 464 | 6.54 | 0.02 |
The analysis of journals can help us to find the effectiveness and provide a reference for us to choose the target journals. Results show that
The top 10 co-cited journals of NPs according to the citation frequency.
No. | Freq | Journal | IF | Centrality | Half-life |
---|---|---|---|---|---|
1 | 1386 | 47.661 | 0.10 | 7 | |
2 | 1359 | 2.267 | 0.18 | 7 | |
3 | 1109 | 79.258 | 0.11 | 7 | |
4 | 796 | 1.635 | 0.03 | 8 | |
5 | 796 | 23.259 | 0.03 | 6 | |
6 | 699 | 53.254 | 0.06 | 7 | |
7 | 693 | 4.580 | 0.05 | 8 | |
8 | 665 | 19.384 | 0.09 | 7 | |
9 | 631 | 5.515 | 0.09 | 6 | |
10 | 621 | 4.843 | 0.04 | 8 |
The top 10 co-cited journals of NPs according to the strength of burst.
No. | Burst | Freq | Journal | Centrality | Half-life |
---|---|---|---|---|---|
1 | 41.35 | 209 | 0 | 4 | |
2 | 36.92 | 137 | 0 | 2 | |
3 | 36.76 | 108 | 0 | 1 | |
4 | 35.89 | 134 | 0 | 2 | |
5 | 32.42 | 185 | 0.01 | 7 | |
6 | 31.42 | 125 | 0 | 2 | |
7 | 24.81 | 73 | 0 | 1 | |
8 | 24.61 | 210 | 0.03 | 4 | |
9 | 21.59 | 56 | 0 | 2 | |
10 | 21.01 | 119 | 0 | 3 |
The top 10 funding institutions according to the frequency.
No. | Funding institution | Freq | Proportion (%) | Half-life |
---|---|---|---|---|
1 | Agency for Healthcare Research and Quality | 39 | 0.79 | – |
2 | National Institute for Health Research | 22 | 0.45 | – |
3 | National Institutes of Health | 17 | 0.35 | 9 |
4 | National Institute of Nursing Research | 15 | 0.31 | – |
5 | National Institute on Aging | 15 | 0.31 | 9 |
6 | Canadian Institutes of Health Research | 14 | 0.29 | 9 |
7 | National Cancer Institute | 12 | 0.24 | – |
8 | NINR NIH HHS | 12 | 0.24 | – |
9 | AHRQ HHS | 12 | 0.24 | – |
10 | NCI NIH HHS | 11 | 0.22 | – |
The analysis of the co-cited references, especially the citation burst, can show a significant increase in the fields in which researchers are interested. This study listed the highest citation count references and their strength of burst from 2007 to 2018 and formed a knowledge map (Table 7, Figure 4). The paper “The Role of Nurse Practitioners in Reinventing Primary Care” 23 owns the highest citation counts with 72, and was written by Naylor MD, 2010. It was published in the journal
The top 10 co-cited references in NPs according to the citation frequency.
No. | Citation freq | Author | Title | Year | Source | Burst |
---|---|---|---|---|---|---|
1 | 72 | Naylor MD (Alston, Norton et al. 1995) | The Role of Nurse Practitioners in Reinventing Primary Care | 2010 | Health affairs | 11.32 |
2 | 62 | Newhouse RR (Newhouse, Stanik-Hutt et al. 2011) | Advanced Practice Nurse Outcomes 1990–2008: A Systematic Review | 2011 | Nursing economic$ | 10.94 |
3 | 57 | Horrocks S (Horrocks, Anderson et al. 2002) | Systematic Review of Whether Nurse Practitioners Working in Primary Care Can Provide Equivalent Care to Doctors | 2002 | British medical journal | 21.60 |
4 | 53 | Kleinpell RM (Kleinpell, Ely et al. 2008) | Nurse Practitioners and Physician Assistants in the Intensive Care Unit: An Evidence-Based Review | 2008 | Critical care medicine | 12.57 |
5 | 47 | Moote M (Moote, Krsek et al. 2011) | Physician Assistant and Nurse Practitioner Utilization in Academic Medical Centers | 2011 | American journal of medical quality | 9.44 |
6 | 42 | Petterson SM (Petterson, Liaw et al. 2012) | Projecting US Primary Care Physician Workforce Needs: 2010–2025 | 2012 | Annals of family medicine | 7.54 |
7 | 40 | Kuo YF (Kuo, Loresto Jr et al. 2013) | States with the Least Restrictive Regulations Experienced the Largest Increase in Patients Seen by Nurse Practitioners | 2013 | Health affairs | 13.20 |
8 | 37 | Auerbach DI (Auerbach 2012) | Will the NP Workforce Grow in the Future: New Forecasts and Implications for Healthcare Delivery | 2012 | Medical care | 11.51 |
9 | 36 | Green LV (Green, Savin et al. 2013) | Primary Care Physician Shortages Could Be Eliminated through Use of Teams, Nonphysicians, and Electronic Communication | 2013 | Health affairs | 7.20 |
10 | 35 | Martinez-Gonzalez NA | Substitution of Physicians by Nurses in Primary Care: A Systematic Review and Meta-Analysis | 2014 | BMC health services research | 11.53 |
Keywords can provide an insight into the main research topics in this research field clearly.25 From Table 8 and Figure 5, we can see the top 10 keywords according to the occurrence frequency, which is not difficult to detect, are “nurse practitioner” (982), “care” (562), and “nurse” (555), which have the most occurrences. In addition to these, “primary care,” “education,” and “management” are more active in this field of study, and are capable of functioning as the hot-point at present or had done so previously.
The top 10 keywords according to the occurring frequency.
No. | Occurring freq | Keywords |
---|---|---|
1 | 982 | Nurse practitioner |
2 | 562 | Care |
3 | 555 | Nurse |
4 | 461 | Primary care |
5 | 376 | Education |
6 | 376 | Management |
7 | 326 | Outcome |
8 | 323 | Physician |
9 | 297 | Impact |
10 | 267 | Health |
We also analyze the burst strength of the keywords
From the overlay maps results, we can mainly analyze the knowledge transfer in this field.26 As we can see, it is possible to discern a contrasting picture between the citing base map on the left and the cited base map on the right (Figure 7). As the result shows, there are 2 principal wire bundles, the one from “Medicine, Medical, Clinical” to “Health, Nursing, Medicine”, and the other one from “Psychology, Education, Health” to “Health, Nursing, Medicine.” We can draw a conclusion that the studies on the NPs have taken into account the clinical and nursing aspects, to be their references. Hence, if we continue to do research about NPs, we can pay attention in this direction.
The development tendency of publications shows that the count of papers is growing every year, from 2007 to 2018 and the average of published papers is 409.33 (8.33%). The highest publication count reaches 618 (12.58%) in 2018. This suggests that many countries pay attention to the NP in recent years. For instance, Canadian Nurses Association has made relevant rules on NP resources, profiles, exam education, and so on.8 American Association of Nurse Practitioners includes clinical resources, practice management, professional development, and practice-related research.12 However, there is no such association for NP at present in China. More research should be done in the future to address this issue.
The authors analysis showed that not a core group of authors formed. This may be attributable to the fact that the beginning time in this field is too late. However, there were also many productive authors, like Gardner G, Gardner A, and Hooker RS.
From the perspective of journal analysis, we can see the most productive journal is
From the results of the co-cited journal, we may make some conclusions as follows: Among the top10 co-cited journals, 50% of the journals own the higher IF, which is over 10, such as
From the results of citation frequency, we can get some effective information. There are some references related to “Primary Care,” which accounted for 50%. The “Primary Care” became mainly a direction and hot point in the research about NPs. In addition, there are few researches which are related to clinical nursing about NP and its further development. Not only “nurse practitioner,” “care,” and “nurse” but also “primary care,” “education,” and “management” have gradually become the principal points at this stage.
From the analysis of country and institution, we can see that the most productive ones were in Europe and north America. This is because nursing care originates from there and their nursing system is more complete than that of others. From the knowledge map of country analysis, the existence of a link between countries can be inferred but the strength of the link is lower. Enhancing the cooperation between countries about NPs is important in the future. Also, it is important to select the development model according to the nation's conditions, since such a selection would be appropriate for the development of senior NPs. From the visual map of institutions, there are some subjects about NP's studies, such as “emergency care,” “chronic kidney disease,” “novel approach,” and so on. Especially, the University of Michigan and the University of California, San Francisco have become the vital research centers and others are assembled around them to develop themselves. These 2 centers put forth a good example for others to make progress in the future.
Finally, we analyze the grant of these studies. The “Agency for Healthcare Research and Quality” (39, 0.79%), “National Institute for Health Research” (22, 0.45%), and “National Institutes of Health” (17, 0.35%) own the highest proportion of funding support. In addition, the “National Institutes of Health” is an institution which not only has the highest proportion of funding support but also has long-duration support. That grant is more crucial to a study which affects the continuation of a study and the publication of research findings. Therefore, funding support from governments should last for a long duration if they choose a study that contributes to the development of society and academy. This will promote the development of NP.
Since it was too late when the study on NP began (2007), there were no core group of authors formed according to the centrality. In our study, we found that there are some highly productive authors, but they just do some researches themselves or cooperate with their own teammates, and so no team that works internationally has been developed. Furthermore, since the hot topic of research in this field is somewhat narrow, it is necessary to ascertain more points by which we can do multifaceted researches using the available big data and experience. In the future, we can carry out more studies on NPs and do more research to discover some new points.
Because the capacity of CiteSpaceV software for data is limited (10,000), there are some data do with the minimum spanning tree and pruning sliced networks. So, the data were simplified, and only then could they authentically reflect the level of development to some extent.