Classic Citations in Main Primary Health Care Journals: A PRISMA-Compliant Systematic Literature Review and Bibliometric Analysis.

The impact of a publication in a particular medical area is reflected by the number of times the article is included as a citation. It is not known, however, which articles are cited the most in primary care journals. In our study, we aimed to identify the 100 most cited articles in primary care medicine and analyze their characteristics.We searched the Science Citation Index Expanded for articles published in 18 primary care journals using the subject category "Primary health care." We identified 100 articles in primary health care that were the most cited. We analyzed the characteristics of these articles using the title, number of citations, citation density, year of publication, journal source, decade published, country of origin, institution, author names, and type of article.The 100 articles that were cited the most were published between the years 1977 and 2009. The 1990s decade was the most productive decade. The number of citations ranged from 117 to 775. The articles were published in 9 journals and the journal with the largest number of most cited articles (n = 33) was the Journal of Family Practice. This was followed by the British Journal of General Practice (n = 17) and the journal Family Practice (n = 16). The United States was the most productive country (n = 59); the United Kingdom was next (n = 25) and this was followed by Canada (n = 5) and The Netherlands (n = 5). The most popular article type was a review article and this was followed by a qualitative study and then methodological study.Our study provides insight into the historical development of primary care studies, based on citations, and provides the foundation for further investigations.

INTRODUCTION

According to The Declaration of Alma-Ata, primary health care is essential health care based on scientifically sound and socially acceptable methods. It should be universally accessible to individuals and families, with their full participation, at a cost that is affordable in the community and country and should be carried out in a spirit of self-reliance and self-determination.[1] The purpose of a primary health care system is to provide better health for all. Many articles have been published on primary health care over a number of years, and the numbers of papers being published is increasing. Some classic papers have had dramatic effects on the promotion of primary health care. There has been little work, however, to identify these classic papers.

Many methods have been developed to evaluate the significance of scientific papers, and assessing citations is one of them. A citation is acknowledgement that a paper referenced a previously published article. A citation indicated the paper contributed something valuable to the field. Currently, citation analysis is widely used to evaluate the significance of published studies.[2-4] Citation analysis is a bibliometric method that assesses the number of times an article is cited in other articles and it is considered to be a reliable approach for ranking articles. Articles that are cited often are thought of as having had a scientific impact. A well-cited article indicates it is a valuable paper in its field.[5,6] Web of Science is often used to analyze citations in various medical fields, including respiratory medicine,[7] oncology,[8] emergency medicine,[9] critical care medicine,[10] rehabilitation,[11] otolaryngology,[12] obstetrics and gynecology,[13] ophthalmology,[14] anesthesiology,[15] dermatology,[16] nursing research,[17] trauma,[18] urology,[19] radiology,[20] general surgery,[21] neurosurgery,[22] and integrative and complementary medicine.[23] Analyzing citations has made it possible to develop a better understanding of the characteristics of classic papers.

To date, no study has analyzed the most cited papers in the field of primary health care. Our aim was to identify the 100 most cited papers in primary health care and to determine the principal characteristics of these papers.

METHODS

The Research Ethics Committee of The 306th Hospital of the People's Liberation Army and Guang’anmen Hospital approved this study. We used the design of previous publications as models for the design of this study.[7-23] The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement.[24]

A search with Science Citation Index Expanded of the ISI Web of Science (Thomson Reuters, Philadelphia, PA) was performed on December 6, 2014, which was conducted in a similar manner to previous studies.[5,6,16-18,21,25,26] There were 18 journals found with the subject category “Primary health care” in Journal Citation Reports (JCR) for the year 2013. All 18 journals were used in our study (Table 1).

TABLE 1

List of Journals That Were Search With the Topic Heading “Primary Health Care” in the Web of Science

We used the “OR” operator when placing the journal titles in the search window so that all articles published in the 18 journals were included. We recorded the 100 articles that were cited the most in relation to primary health care. The basic information was recorded and then analyzed according to the methods of previous studies.[5,18,19,23,27] We included the title, number of citations, journal source, citation density, year of publication, decade the article was published, country of origin, institution, author names, and type of article. The address provided for the first author was used to determine the institution and country of origin. The citation density was calculated using the total number of citations divided by the number of years since publication.

RESULTS

Table 2    shows the number of citations and top 100 articles. The number of citations was 117 to 775 (Table 2   ). For the 100 most cited papers, the mean number of citations was 186. The oldest article was published in 1977 and it was ranked number 52. The newest articles were published in 2009 and the 3 articles published in 2009 were listed as 30, 31, and 36. The decade of the 1990s had the most articles (n = 50) and the 2000s had 41 articles, the 1980s had 7, and the 1970s had 2 published articles.

TABLE 2

List of top 100 Articles for Number of Citations in the Field of Primary Health Care

All of the articles in the top 100 list were written in English. Of the 18 journals, 9 contained articles in the top 100 list (Table 3). Most of the papers were published in the Journal of Family Practice (n = 33), and then the British Journal of General Practice (n = 17), and then Family Practice (n = 16). Ten countries contributed articles to the top 100 articles (Table 4). The most common country of origin was the United States (n = 59), then the United Kingdom (n = 25), Canada (n = 5), and finally The Netherlands (n = 5). Eighty institutions contributed articles to the 100 most cited articles. The institution that contributed the most articles was The University of Western Ontario (n = 3) and then the School of Medicine, Oregon Health & Science University (n = 3; Table 5).

TABLE 2 (Continued)

List of top 100 Articles for Number of Citations in the Field of Primary Health Care

TABLE 2 (Continued)

List of top 100 Articles for Number of Citations in the Field of Primary Health Care

TABLE 2 (Continued)

List of top 100 Articles for Number of Citations in the Field of Primary Health Care

Some authors were represented in the top 100 list multiple times. Bertakis KD was the most common first author (n = 3) and Elwyn G was next (n = 2). They were followed by Mainous AG 3rd (n = 2), Safran DG (n = 2), Saultz JW (n = 2) Smilkstein G (n = 2), and finally Williams S (n = 2). The most common type of article in the top 100 was a review article (n = 31), following by qualitative research (n = 27) and then a methodological study (n = 12; Table 6).

TABLE 3

List of Top 100 Articles According to Source Journal

The mean number of citations per year, which is considered the citation density, showed that the article by Viera and Garrett[28] was the top paper, and this paper was followed by one by Stewart et al[29] and one by Rubak et al (Table 2   ).[30] The article with the most citations (86 citations per year) was by Viera and Garrett.[28] This study was a methodological study that was published in 2005 and investigated the kappa statistic as an assessment of interobserver agreement. A cohort study by Stewart et al[29] (2000) had 48 citations per year and it investigated the impact of patient-centered care on outcomes. This study had the second most citations. The study with the third most citations was a systematic review. It was a meta-analysis by Rubak et al[30] (2005) and had 48 citations per year.

DISCUSSION

There has been much growth in research on primary health care in the last several decades.[31] A large number of papers have been published on this topic. To understand the history and development of primary health care, we identified the classic articles that have been published. This will be helpful when designing future research studies. Our citation analysis is a widespread, common type of analysis that has been performed in many other fields of medicine.[7-23] Our study was the first to analyze the most cited articles in the field of primary health care. The top 100 list of articles can be used to identify the milestone articles in the field of primary health care,[25,32] and it shows the institutions and authors that have contributed to these landmark papers. It also allows identification of the authors that have subsequently led the field of primary health care.[27,33] Our study also provides useful information about what is required for a paper to be considered as a classic paper.[5,34] In addition, it can be a useful tool for the education of residents and fellowship directors in how classic articles in primary health care can become familiar papers.[26]

There were 117 to 775 citations of the top 100 most cited articles in primary health care. This number was lower than other subspecialties such as hypertension (582–7248),[35] and the number was higher than other fields, such as integrative and complementary medicine (52–503).[23] This shows that different subspecialties have different citation rates. The size of the scientific community in the field can be a possible reason for this.[33] Most of the articles were published in the 1990s and 2000s, which was much later than articles published in other fields of medicine.[8,18,32] Therefore, primary health care can be seen as a relatively “young” field. Primary health care was adopted in the declaration of the International Conference on Primary Health Care, which was held in Alma Ata, Kazakhstan in 1978. This conference addressed a wide range of research issues in the 1990s.[31]

There were 10 countries that contributed to the top 100 list of the most cited articles in primary health care. The majority of the most cited papers came from the United States. It is not surprising that the United States led the ranking because it is at the top of the list for many other fields of medicine, such as anesthesiology,[15] the respiratory system,[7] general surgery,[21] radiology,[20] and orthopedics.[32] The results suggest that the United States has great influence on primary health care, which may be due to the large size of the primary health care community and sufficient financial support.[5,19,36-38] In addition, there is a tendency for the authors from the United States to cite articles authored by researchers of the United States.[5,39]

All of the articles in the top 100 list were written in English. The English language seems to be the most frequently used language for primary health care articles. Also, all of the 100 most cited articles were published in 9 journals. The top 3 journals for these publications were the Journal of Family Practice, British Journal of General Practice, and then Family Practice. It has been shown in some previous studies that the impact factor of the journal was the strongest indicator for the number of citations, and most of the journals in which the articles were published had high impact factors.[6,18] This, however, was not demonstrated in our study. Therefore, the impact factor of the journals in our study did not affect the citation numbers, which was similar to findings in other studies.[22]

The authors Bertakis KD, Elwyn G, Mainous AG 3rd, Safran DG, Saultz JW, Smilkstein G, and Williams S have good publication records in primary health care and these authors have great priority in this field. The review articles were the most common type of article in the top 100 list. This finding was consistent with other medical specialties such as nursing research[18] and integrative complementary medicine.[23] Commonly adopting reviews has occurred in other fields as well. Even though randomized controlled trials are thought to provide a high level of evidence, there were only a few in the top 100 list in our study. This may be due to randomized controlled trials requiring long period of treatment during the study and follow-up and also they are highly complex and require tight regulation.

There were several limitations in the study. First, important and influential articles with fewer citations were not included. Second, our search was based on a category to access primary health care journals and the 18 journals did not include all articles published in the field of primary health care. Therefore, papers published in general medical journals were not evaluated.[40-42] Our citation analysis did not evaluate self-citation, citations in textbooks and lectures, or web-based literature.[26,32,43] Also, it is not possible for authors to cite papers from the journal in which they hope to publish their study.[44] Fourth, older articles were favored because the overall number of citations accumulated over a longer period of time. Fifth, the scientific community has a tendency to comply with a paradigm and therefore there is a “snowball effect.”[45] This means that authors may cite certain articles more often simply because they have received numerous citations previously, rather than citing the article for its value. Finally, this study was a cross-sectional study that was performed at a single time point. Results could change if the analysis is performed at another time point.[41,42]

CONCLUSIONS

Our study produced a detailed list of the 100 most cited articles in primary health care and this list was analyzed. The top cited papers were published in English and were most review and qualitative types of studies. The top journal was the Journal of Family Practice, which originates from the United States. Our study may provide information for future analyses to determine the necessary characteristics of classic articles in the field. Our top 100 list of articles provides insight into the history and development of primary health care as a medical specialty and may be the basis for future studies.

TABLE 4

List of Top 100 Articles According to Country of Origin

TABLE 5

List of Institutions of Origin for Articles That Had More Than One Top Cited Article

TABLE 6

List of Type of Article for the Top 100 Articles