Publication years and document types
A total of 962 publications related to FPS were identified in Web of Science Core Collection SCI-Expanded. As illustrated in Figure 2, the research on FPS has demonstrated a consistent upward trend since 2004, peaking with the highest number of publications in 2021, reaching 76 articles. A total of 20,104 citing articles, 31,206 times cited, 32.44 average per item, and 83 h-index were obtained. Table 1 shows the document types of publications that were analyzed, where 72.453% (697) of the publications were articles and 27.547% (265) were review articles.
Table 1 Publication type in FPS
No.
|
Publication Type
|
Total Publications
|
Citing Articles
|
Times Cited
|
Average per item
|
% Of 962
|
H-index
|
1
|
Article
|
697
|
15,229
|
23,013
|
33.02
|
72.453
|
70
|
2
|
Review Article
|
265
|
6,977
|
8,193
|
30.92
|
27.547
|
46
|
Scientific collaboration networks
In bibliometrics, scientific collaboration is measured by the number of papers jointly published. Research collaboration refers to the simultaneous appearance of different authors, institutions or countries/territories in a paper. CiteSpace provides three levels of research collaboration analysis, namely, micro level scholar collaboration network (co-author), meso level institution collaboration network (co-institution), and macro level country/territory collaboration network (co-country/territory). In the research collaboration network obtained by CiteSpace, the size of nodes denotes the number of papers published by authors, institutions, or countries/territories, while connections reflect the strength of cooperation relationships [27].
Co-author and co-cited author
A total of 4,731 authors contributed to involved in FPS. The author is the main body of all scientific research. Combined with the structural characteristics of the author and the cooperative network among the authors, it is usually more direct to identify the core author group and the cooperative relationship among the authors in the research field. Effective cooperation among active scholars can promote the development of FPS. Table 2 and Figure 3 present the results of the visualization analysis for FPS authors. Nodes signify authors, connections denote collaborations, and node size indicates the author’s contribution level, with larger nodes representing more published articles.
From Table 2, the top three authors with the highest frequency in co-author are Bargagli E (27), Baughman RP (24), and Valeyre D (19), all with centrality of 0.01. The top three authors with the highest frequency in co-cited authors are Baughman RP (296), Raghu G (265), and Huntinghake GW (229). The centrality of Baughman RP (0.29), Raghu G (0.10), and Judson MA (0.10) is greater than 0.1. This indicates that Baughman RP and Raghu G have a high volume and quality of publications, and have a strong influence in this field.
Figure 3 displays two distinct cooperative networks among authors. In Figure 3A, a network was obtained with 4,529 nodes, 15,458 connections and a density of 0.0015, Modularity Q=0.9813, Weighted Mean Silhouette S=0.9889, and Harmonic Mean (Q, S) =0.9851. Baughman RP, Judson MA and Grutters JC worked closely together. Bargagli E worked closely with Rottoli P and Landi C and Sestini P. Wells AU, Antoniou KM and Bouros D worked closely together. Co-cited authors refer to two or more authors who are simultaneously cited in another paper or papers, thus forming a co-cited relationship. Author co-citation analysis refers to the analysis of the frequency at which literature published by different authors is simultaneously cited by other authors, in order to determine the distance of research interests between authors.
As shown in Figure 3B, a network was obtained with 391 nodes, 2,019 connections and a density of 0.0265, Modularity Q=0.9813, Weighted Mean Silhouette S=0.9889, and Harmonic Mean (Q, S) =0.9851. This analysis provides insights into the interconnected relationships among authors, enriching the understanding of collaborative dynamics within the FPS research landscape.
Table 2 Top 10 authors in FPS
Rank
|
Author
|
Freq
|
Year
|
Centrality
|
Affiliation
|
Co-Cited Author
|
Freq
|
Year
|
Centrality
|
Affiliation
|
1
|
Bargagli E
|
27
|
2007
|
0.00
|
University of Siena
|
Baughman RP
|
296
|
2004
|
0.29
|
University System of Ohio; University of Cincinnati
|
2
|
Baughman RP
|
24
|
2007
|
0.00
|
University System of Ohio; University of Cincinnati
|
Raghu G
|
265
|
2004
|
0.10
|
University of Washington Seattle
|
3
|
Valeyre D
|
19
|
2006
|
0.00
|
Institut National de la Sante et de la Recherche Medicale (Inserm)
|
Hunninghake GW
|
229
|
2004
|
0.03
|
University of Iowa
|
4
|
Wells AU
|
18
|
2007
|
0.00
|
Guy's & St Thomas' NHS Foundation Trust
|
Judson MA
|
142
|
2004
|
0.10
|
Albany Medical College
|
5
|
Nunes H
|
17
|
2007
|
0.00
|
Hopital Universitaire Avicenne –Assistance Publique Hopitaux Paris (APHP); Inserm; Universite Paris 13
|
King TE Jr
|
131
|
2004
|
0.03
|
University of California San Francisco School of Medicine
|
6
|
Mueller-quernheim J
|
15
|
2007
|
0.00
|
University of Freiburg
|
Wells AU
|
127
|
2004
|
0.02
|
Guy's & St Thomas' NHS Foundation Trust
|
7
|
Rottoli P
|
14
|
2005
|
0.00
|
University Hospital of Siena
|
Flaherty KR
|
119
|
2006
|
0.06
|
University of Michigan System
|
8
|
Prasse A
|
14
|
2007
|
0.00
|
Hannover Medical School
|
Nunes H
|
114
|
2004
|
0.06
|
Hopital Universitaire Avicenne –Assistance Publique Hopitaux Paris (APHP); Inserm; Universite Paris 13
|
9
|
Bergantini L
|
14
|
2007
|
0.00
|
Siena University Hospital Department of Medical Sciences
|
Shorr AF
|
112
|
2004
|
0.07
|
MedStar Washington Hospital Center
|
10
|
Grunewald J
|
13
|
2019
|
0.00
|
Karolinska Institute Department of Medicine Solna
|
Travis WD
|
111
|
2004
|
0.03
|
Memorial Sloan Kettering Cancer Center
|
Co-country/territory and co-institution
A total of 962 publications were published from 68 different countries/territories and 1,387 institutions. As shown from Table 3, the USA (302) leads with the highest number of publications, followed by Italy (118), Germany (102), and England (100). The centrality of USA (0.46), England (0.26), and Netherlands (0.11) are all greater than 0.1, indicating that these countries have significant influence in the field of FPS. USA has the highest frequency and the centrality of 0.46, indicating its crucial position in FPS research. Analyzing the cooperation network of research institutions, CiteSpace identifies high-impact researchers and their collaborations in FPS. An examination of research institutions distribution reveals that Assistance Publique Hopitaux Paris (APHP) boasts the highest frequency at 41, although with a centrality of 0.03. The Royal Brompton Hospital (0.10), Imperial College London (0.14), and the University of California System (0.10) all exhibit centralities greater than 0.1, indicative of these institutions’ contributions to high-quality FPS publications.
In Figure 4, the close connections between countries/territories and institutions are visually represented. As depicted in Figure 4A, a network emerges with 68 nodes, 321 connections, density of 0.1409, Modularity Q=0.9813, Weighted Mean Silhouette S=0.9889, and Harmonic Mean (Q, S) = 0.9851. Notably, three purple nodes in Figure 4A signify USA, England, and Netherlands, underscoring their central roles. In Figure 4B, a network is observed with 449 nodes, 1,831 connections, density of 0.0182, Modularity Q=0.9813, Weighted Mean Silhouette S=0.9889, and Harmonic Mean (Q, S) =0.9851. The purple nodes in Figure 4B represent institutions with a centrality greater than or equal to 0.1, highlighting their significant contributions to FPS research.
Table 3 Top 10 countries/regions and institutions in FPS
Rank
|
Countries/Regions
|
Frequency
|
Centrality
|
Year
|
Institution
|
Frequency
|
Centrality
|
Year
|
1
|
USA
|
302
|
0.46
|
2004
|
Assistance Publique Hopitaux Paris (APHP)(France)
|
41
|
0.03
|
2004
|
2
|
Italy
|
118
|
0.08
|
2004
|
University of Siena (USA)
|
37
|
0.00
|
2005
|
3
|
Germany
|
102
|
0.04
|
2004
|
Royal Brompton Hospital (England)
|
35
|
0.10
|
2006
|
4
|
England
|
100
|
0.26
|
2004
|
St. Antonius Hospital Utrecht (Netherlands)
|
35
|
0.04
|
2005
|
5
|
Japan
|
74
|
0.06
|
2004
|
University System of Ohio (USA)
|
35
|
0.04
|
2007
|
6
|
Netherlands
|
63
|
0.11
|
2005
|
Universite Pairs Cite (France)
|
33
|
0.01
|
2004
|
7
|
France
|
63
|
0.06
|
2004
|
Imperial College London (England)
|
31
|
0.14
|
2006
|
8
|
Poland
|
46
|
0.00
|
2004
|
University of London (England)
|
29
|
0.05
|
2005
|
9
|
China
|
44
|
0.00
|
2008
|
University of Cincinnati (USA)
|
29
|
0.03
|
2007
|
10
|
Spain
|
39
|
0.02
|
2005
|
University of California System (USA)
|
28
|
0.11
|
2005
|
Co-cited journal and journal overlay map
Co-cited journal
We found that 962 publications related to FPS were published in 334 journals. CiteSpace was used to process the downloaded literature and obtain the knowledge map of journal co-occurrence (Figure 5A). Figure 5A shows the network visualization maps for citation analysis of journals that are active in FPS. A network was obtained with 151 nodes, 935 connections and a density of 0.0826, Modularity Q=0.3695, Mean Silhouette S=0.7831 and Harmonic Mean (Q, S) =0.5021. In the journal co-citation network map, the size of the node is proportional to the number of citations of the journal; the larger the node, the greater the number of citations of the journal. The lines in the network represent the co-citation relationship between journals; the closer the co-citation relationship, the wider the lines. When the nodes are in tree ring style, the trend reflected by the colors of the lines and nodes can be judged by referring to the colors above the network diagram [27]. In the current network diagram, the network connections transition from purple to red, and the closer the connections are to red, the closer the co-citation relationship is to 2024.
As shown in Table 4, Sarcoidosis Vasculitis and Diffuse Lung Diseases (69) had the highest number of publications, followed by Respiratory Medicine (52) and Current Opinion in Pulmonary Medicine (39). Among the top ten journals, European Respiratory Journal (24.90) had the highest impact factor (IF). Furthermore, as shown in Table 4 that 40% of journals belong to Q1. Among the top ten co-cited journals, nine journals have been cited more than 300 times. As shown in Table 4, the journals with the highest IF are Lancet (168.90), followed by New England Journal of Medicine (158.50) and European Respiratory Journal (24.90). According to the 2023 Journal citation report (JCR), almost all the co-cited journals in the top ten journals were in the Q1 region, except for Respiratory Medicine and Current Opinion in Pulmonary Medicine.
Table 4 Top 10 journals and co-cited journals in FPS
Rank
|
Journal
|
Record Count
|
IF (2023)
|
JCR
|
Co-cited Journal
|
Freq
|
Centrality
|
IF (2023)
|
JCR
|
1
|
Sarcoidosis Vasculitis and Diffuse Lung Diseases
|
69
|
1.6
|
Q4
|
American Journal of Respiratory and Critical Care Medicine
|
838
|
0.11
|
24.7
|
Q1/Q1
|
2
|
Respiratory Medicine
|
52
|
4.3
|
Q2/Q2
|
European Respiratory Journal
|
764
|
0.10
|
24.9
|
Q1
|
3
|
Current Opinion in Pulmonary Medicine
|
39
|
3.3
|
Q3
|
Chest
|
739
|
0.06
|
10.1
|
Q1/Q1
|
4
|
Chest
|
33
|
10.1
|
Q1/Q1
|
Thorax
|
582
|
0.04
|
10.0
|
Q1
|
5
|
European Respiratory Journal
|
31
|
24.9
|
Q1
|
New England Journal of Medicine
|
466
|
0.09
|
158.5
|
Q1
|
6
|
Seminars in Respiratory and Critical Care Medicine
|
23
|
3.2
|
Q3/Q3
|
Respiratory Medicine
|
456
|
0.02
|
4.3
|
Q2/Q2
|
7
|
American Journal of Respiratory and Critical Care Medicine
|
20
|
24.7
|
Q1/Q1
|
Sarcoidosis Vasculitis and Diffuse Lung Diseases
|
448
|
0.02
|
1.6
|
Q4
|
8
|
Respirology
|
20
|
6.9
|
Q1
|
Lancet
|
314
|
0.02
|
168.9
|
Q1
|
9
|
Lung
|
17
|
5
|
Q2
|
Current Opinion in Pulmonary Medicine
|
302
|
0.04
|
3.3
|
Q3
|
10
|
BMC Pulmonary Medicine
|
15
|
3.1
|
Q3
|
American Journal of Physiology Lung Cellular and Molecular Physiology
|
292
|
0.05
|
4.9
|
Q1/Q2
|
In the co-citation network of journals, the journals were divided into different groups by network clusters. Through the results of clusters, it is helpful to understand the knowledge base of the journal dimension in the field of concern and the knowledge structure of the meso-view represented by the journal [27]. Figure 5B shows the cluster view of co-cited journals. A network was obtained with 151 nodes, 935 connections and a density of 0.0826, Modularity Q=0.3695, Mean Silhouette S=0.7831 and Harmonic Mean (Q, S) =0.5021. Five prominent clusters emerge from Figure 5B, with the cluster size inversely proportional to the number. The size of a cluster indicates the number of members it contains. Additionally, the mean year represents the average publication year of literature in the cluster, offering insights into the temporal distance of cited references within the cluster [27].
The largest cluster (#0) has 43 members and a silhouette value of 0.9. It is labeled as systemic sclerosis by LLR. The most cited members in this cluster are: American Journal of Physiology-Lung Cellular and Molecular Physiology (161), Journal of Rheumatology (96), and Rheumatology (75). The average year of journals in the cluster is 2019, and the most cited reference in this cluster is “Mechanisms and Management of Cough in International Lung Disease” by Rasheed AZ in Expert Review of Respiratory Medicine [28]. The second largest cluster (#1) has 39 members and a silhouette value of 0.74. It is labeled as ILD by LLR. The most cited members in this cluster are: American Journal of Respiratory and Critical Care Medicine (838), European Respiratory Journal (764), and Chest (739). The average year of journals in the cluster is 2007, and the most cited reference in this cluster is “Sarcoidosis: Updates on therapeutic drug trials and novel treatment approaches” by Obi ON in Frontiers in Medicine [29]. The third largest cluster (#2) has 30 members and a silhouette value of 0.735. It is labeled as PH by LLR. The most cited members in this cluster are: American Journal of Physiology Lung Cellular and Molecular Physiology (292), Journal of Immunology (266), and Respiratory Research (248). The average year of journals in the cluster is 2008, and the most cited reference in this cluster is “The clinical and immunologic features of pulmonary fibrosis in sarcoidosis.” by Patterson KC in Translational Research [30]. The 4th largest cluster (#3) has 19 members and a silhouette value of 0.815. It is labeled as pulmonary sarcoidosis by LLR. The most cited members in this cluster are: American Journal of Medicine (145), Sarcoidosis (74) and Archives of Internal Medicine (45). The average year of journals in the cluster is 2016, and the most cited reference in this cluster is “Common Variable Immunodeficiency.” by Remiker A in Medical Clinics of North America [31]. The 5th largest cluster (#4) has 9 members and a silhouette value of 0.848. It is labeled as advanced fibrocystic lung diseases by LLR. The most cited members in this cluster are: Radiology (200), American Journal of Roentgenology (181) and European Radiology (60). The average year of journals in the cluster is 2009, and the most cited reference in this cluster is “Assessing fibrosis in pulmonary sarcoidosis: late-enhanced MRI compared to anatomic high-resolution computed tomography (HRCT) imaging.” by Brady D in QJM: An International Journal of Medicine [32]. In general, the focus of these journals is on the evaluation, clinical and immunological characteristics, and treatment in FPS.
Journal overlay map
Journal overlay map can be used to analyze and display information such as the distribution, citation trajectory, and center of gravity drift of papers from various disciplines. In the dual-map overlay results, the left side represents the citing map, while the right side represents the cited map. The curve is a citation line used to show the context of the citation. In the left map, the longer the horizontal axis of the ellipse, the more papers were published in the corresponding journal. The longer the vertical axis of the ellipse, the more authors it represents [27].
In Figure 6, the dual map overlay of journals shows the distribution of topics. We can see the most important three paths. The two green citation paths indicate that research in Medicine, Medical, Clinical journals are frequently cited Molecular, Biology, Genetics journals and Health, Nursing, Medicine journals. The yellow citation path indicates that research in Molecular, Biology, Immunology journals are frequently cited Molecular, Biology, Genetics journals. This indicates that the research in FPS is predominantly focused on Molecular, Biology, Medicine and Genetics journals.
Co-cited reference and references bursts
Co-citation analysis refers to the situation where two articles appear together in the reference list of the third cited article, and these two articles form a co-citation relationship. Document co-citation analysis, a distinctive and advantageous feature of CiteSpace, entails the exploration of co-citation relationships within a spatial dataset of documents. By opting for the co-cited reference node type, it becomes possible to analyze the research frontiers and knowledge foundation in FPS. The knowledge foundation comprises a set of co-cited references, while the research frontiers consist of collections of citing references that refer to these knowledge foundations [27].
Co-cited reference
Figure 7A shows the co-citation network for FPS. A network was obtained with 670 nodes, 2,508 connections and a density of 0.0112, Modularity Q=0.3695, Mean Silhouette S=0.7831 and Harmonic Mean (Q, S) = 0.5021. In the reference co-citation network, the node’s size is proportional to the citation times of the paper. The larger the node, the higher the citation times of the paper. If there is a connection between two nodes, it indicates that the reference corresponding to the two nodes has a co-citation relationship. The color of the connecting lines denotes the time when two papers were initially co-cited. Analyzing the color shifts of co-referenced lines across the entire network allows for an examination of research trends and evolution within the field [27].
From co-cited references retrieved, the top ten co-cited references are shown in Table 5. Among the top ten co-cited references, four guidelines were idiopathic pulmonary fibrosis (IPF): evidence-based guidelines for diagnosis and management [33], diagnosis of IPF [34], diagnosis and detection of sarcoidosis [2] and an update of the international multidisciplinary classification of idiopathic interstitial pneumonia [35]. Additionally, clinical trials on pulmonary sarcoidosis [36, 37]; sarcoidosis associated pulmonary hypertension (SAPH) [38] and predictors of mortality in pulmonary sarcoidosis [14]. Among the top three co-cited references, “Nintedanib in progressive fibrosing interstitial lung diseases” [37] was the most frequently cited. The “An Official ATS/ERSARS/ALAT Statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management” [33] was the second most cited. The “Diagnosis of idiopathic pulmonary fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline” [34] was the third most cited article.
Specifically, these are representative articles in FPS. “Nintedanib in progressive fibrosing interstitial lung diseases” [37] is an article by Flaherty KR et al. published in New England Journal of Medicine in 2019. The authors conducted a multinational, multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase III trial to evaluate Nintedanib (150mg, twice daily) in 663 patients with fibrotic lung disease and a relative FVC decline ≧10%. Twice-daily in the treatment of progressive fibrotic ILD. The results showed that the annual rate of decline in FVC was significantly lower in patients receiving Nintedanib than in those receiving placebo. The main adverse reactions of Nintedanib were gastrointestinal reactions, including diarrhea, abdominal pain, and elevated liver enzymes
“An Official ATS/ERSARS/ALAT Statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management” [33] is an article published in American Journal of Respiratory and Critical Care Medicine by Raghu G et al. in 2011. This article is an international evidence-based guideline on the diagnosis and management of IPF, and its main aim is to enable clinicians to explain these recommendations in the context of individual patient values and preferences, and make appropriate decisions regarding various aspects of disease management for the typical IPF patient.
The article “Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline” [34] was published in American Journal of Respiratory and Critical Care Medicine by Raghu G et al. in 2018. This significant contribution not only updates the diagnostic criteria for IPF but also provides crucial clinical recommendations for the accurate diagnosis of this condition.
References bursts
The burst detection provided by CiteSpace can extract emerging words from topic words in references, and clearly show the research frontiers and development trends of a certain discipline [42]. In this study, references burst detection was conducted based on co-cited references network, and the top twenty-five references with the strongest citation bursts were obtained in FPS (Figure 7B). Here, “begin” denotes the starting year, “end” represents the concluding year, and “year” indicates the year in which the document was published.
The strength of the first ranked article is 24.65. It is “An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management.” by Raghu G et al., published in the American Journal of Respiratory and Critical Care Medicine in 2011 [33]. The strength of the second ranked article is 22.49, which was published by Flaherty KR et al. in 2015 in the New England Journal of Medicine titled “Nintedanib in Progressive Fibrosing Interstitial Lung Diseases.” [37]. The strength of the third ranked article is 17.60, which was published by Raghu G et al. in 2018 in American Journal of Respiratory and Critical Care Medicine titled “Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline.” [34]. The three articles obtained are consistent with the co-cited references, indicating that these three articles play an important role in FPS.
According to the sort by the beginning year of burst, the information provided by the reference in the year closest to the present can be considered as the research frontier in FPS. By analyzing ten articles with an end of 2024, four of them serve as guidelines. Two articles involve Nintedanib, a tyrosine kinase inhibitor that interferes with the proliferation, migration and differentiation of fibroblasts, as well as the secretion of extracellular matrix components in the lung, has anti-fibrotic properties and is recommended in guidelines for the treatment of patients with IPF [37, 43].
In addition, we also obtained three articles with centrality greater than or equal to 0.10. These three references [14, 36, 39] have had a profound impact on the development of this field. “Sarcoidosis.” is a review published by Valeyre D et al. in 2014 on Lancet [39]. Its centrality is 0.10 and citations are 732, making it a highly cited paper. This article provides new insights into the diagnosis, care, and prognosis of sarcoidosis. “Predictors of mortality in pulmonary sarcoidosis.” is an article published in Chest by Kirkil G et al. [14] in 2018, with a centrality of 0.24 and citations of 117. This article evaluates the prognostic strength of factors predicting respiratory death in patients with sarcoidosis and conducts at least eight years of follow-up. It is concluded that although most sarcoidosis patients perform well, older patients, those with extensive fibrosis on HRCT scans, or those with PH have an increased mortality rate. “An integrated clinicoradiological staging system for pulmonary sarcoidosis: a case-cohort study.” is an article by Walsh SL et al., published in Lancet Respiratory Medicine in 2014 [36], which has 133 citations. This article believes that the prognosis of patients with pulmonary sarcoidosis can be clearly distinguished by a simple staging system that integrates lung function tests, including the composite physiological index, and two HRCT variables.
Table 5 Top 10 co-cited references in FPS
Rank
|
Freq
|
Centrality
|
Title
|
First Author
|
Journal
|
Year
|
1
|
52
|
0.09
|
Nintedanib in Progressive Fibrosing Interstitial Lung Diseases [37]
|
Flaherty KR
|
New England Journal of Medicine
|
2019
|
2
|
48
|
0.02
|
An Official ATS/ERSARS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence-based Guidelines for Diagnosis and Management [33]
|
Raghu G
|
American Journal of Respiratory and Critical Care Medicine
|
2011
|
3
|
47
|
0.01
|
Diagnosis of Idiopathic Pulmonary Fibrosis. An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline [34]
|
Raghu G
|
American Journal of Respiratory and Critical Care Medicine
|
2018
|
4
|
40
|
0.01
|
Diagnosis and Detection of Sarcoidosis. An Official American Thoracic Society Clinical Practice Guideline [2]
|
Crouser ED
|
American Journal of Respiratory and Critical Care Medicine
|
2020
|
5
|
34
|
0.1
|
Sarcoidosis [39]
|
Valeyre D
|
Lancet
|
2014
|
6
|
32
|
0.03
|
An official American Thoracic Society/European Respiratory Society statement: Update of the international multidisciplinary classification of the idiopathic interstitial pneumonias [35]
|
Travis WD
|
American Journal of Respiratory and Critical Care Medicine
|
2013
|
7
|
31
|
0.00
|
Pulmonary sarcoidosis [40]
|
Spagnolo P
|
Lancet Respiratory Medicine
|
2018
|
8
|
29
|
0.24
|
Predictors of Mortality in Pulmonary Sarcoidosis [41]
|
Kirkli G
|
Chest
|
2018
|
9
|
24
|
0.01
|
Pulmonary hypertension associated with sarcoidosis: mechanisms, haemodynamics and prognosis [38]
|
Nunes H
|
Thorax
|
2006
|
10
|
23
|
0.36
|
An integrated clinicoradiological staging system for pulmonary sarcoidosis: a case-cohort study [36]
|
Walsh SLF
|
Lancet Respiratory Medicine
|
2014
|
Co-keyword and keywords bursts
Keywords are the core of a paper, and the analysis of keywords in CiteSpace can obtain the research hotspots, research trends and knowledge structure in FPS. Research hotspots can be considered as one or more topics that are common concerns of scholars in a certain field. Research hotspots have strong temporal characteristics.
Co-keyword
Figure 8A displays the co-occurrence analysis results for keywords in FPS. A network was obtained with 282 nodes, 1,882 connections and a density of 0.0475, Modularity Q=0.3695, Mean Silhouette S=0.7831 and Harmonic Mean (Q, S) =0.5021. In the co-occurrence map of keywords, the size of nodes represents the frequency of their occurrence, and the connections between them show the co-occurrence relationship and strength.
After running the software, synonymous keywords are merged to get the top twenty keywords co-occurrence networks in FPS, and the results are shown in Table 6. For example, interstitial lung diseases was merged with interstitial lung disease (ILD). As shown in Table 6, keywords with high frequency in this study include IPF (345), sarcoidosis (244), ILD (244), fibrosis (145), PF (140), diagnosis (120), bronchoalveolar lavage (BAL) (99), and expression (98). These keywords reflect the popular research hotspots in FPS.
Based on the co-occurrence map of keywords, the LRF algorithm was applied for cluster analysis, resulting in the formation of eight distinct clusters. Through cluster analysis, the research hotspots in this field can be summarized and the basic knowledge structure can be obtained. A network was obtained with 282 nodes, 1,882 connections and a density of 0.0475, Modularity Q=0.3725, Mean Silhouette S=0.7113 and Harmonic Mean (Q, S) =0.489. Figure 8B shows eight clusters of keywords, with each cluster composed of multiple closely related words. The identified clusters are designated as follows: #0 BAL, #1 PH, #2 ILD, #3 COPD, #4 IPF, #5 lung cancer, #6 PF, and #7 YKL-40.
Keywords bursts
Keyword bursts refers to keywords with a sudden increase in frequency during a certain period of time, which can be used to observe research hotspots in different years and reveal research trends and frontiers in different periods. Citespace was used for keyword burst visualization, and the top twenty-five keywords were obtained. As depicted in Figure 8C, “diagnosis” had the strongest citation bursts, with a maximum burst strength of 5.64, followed by “double blind” and “Cardiac sarcoidosis (CS)” at 5.57 and 5.30, respectively. We have selected keywords with an end of 2024, “prevalence”, “double blind”, “diagnosis”, “update” and “efficacy”. The next nineteen top keywords with the strongest citation bursts were: survival, fluid, quality of life (QoL), ILD, CT, classification, alveolitis, lung fibrosis, cells, clinical features, endothelial growth factor, induced sputum, clinical characteristics, population, poisitron emission tomography, cystic fibrosis, activation, markers, prevalence, and Pirfenidone.
Table 6 Top 20 keywords in FPS
Rank
|
Keyword
|
Freq
|
Degree
|
Centrality
|
Rank
|
Keyword
|
Freq
|
Degree
|
Centrality
|
1
|
idiopathic pulmonary fibrosis
|
345
|
57
|
0.12
|
11
|
bronchoalveolar lavage fluid
|
90
|
41
|
0.10
|
2
|
sarcoidosis
|
244
|
55
|
0.14
|
12
|
systemic sclerosis
|
75
|
47
|
0.09
|
3
|
interstitial lung disease
|
244
|
93
|
0.12
|
13
|
alveolar macrophages
|
73
|
37
|
0.04
|
4
|
fibrosis
|
145
|
51
|
0.08
|
14
|
survival
|
65
|
40
|
0.04
|
5
|
pulmonary fibrosis
|
140
|
33
|
0.04
|
15
|
pulmonary hypertension
|
62
|
36
|
0.06
|
6
|
diagnosis
|
120
|
36
|
0.04
|
16
|
hypersensitivity pneumonitis
|
61
|
38
|
0.05
|
7
|
bronchoalveolar lavage
|
99
|
35
|
0.05
|
17
|
lung
|
59
|
36
|
0.04
|
8
|
expression
|
98
|
41
|
0.07
|
18
|
cells
|
57
|
27
|
0.03
|
9
|
pulmonary sarcoidosis
|
97
|
40
|
0.05
|
19
|
hypertension
|
47
|
57
|
0.11
|
10
|
disease
|
96
|
31
|
0.03
|
20
|
mortality
|
44
|
40
|
0.03
|