The descriptive data, maps, and analyses of authors, journals, article types, institutions, and countries of articles in the RA prognosis field are discussed below. Co-citations of cited authors and references are also included.
Chronological distribution
Based on the search strategy, 2759 publications were included in the analysis. As shown in Fig. 1, the number of citations rose gradually from 2000 until 2017, after which it slowed slightly. Overall, there has been a steady increase in the number of publications on RA prognosis over the past 20 years. Of the total 2759 articles, 892 (33.3%) were published between 2000 and 2011, while 1867 (67.7%) appeared between 2012 and 2021. There was a peak of 234 papers in 2017. Currently, the rate of publication appears to be stable at around 200 papers per year.
Distribution of article types
Figure 2 presents the details of the article types. The article types included article, review, meeting abstract, letter, and others. Meeting abstracts (n = 1595) accounted for 57% of the total number of articles, followed by articles (n = 975), accounting for 35%. There are thus relatively fewer journal articles about RA, and the principal means of communication appears to be by meeting abstract.
Source journals
There were a total of 310 journals publishing in the RA prognosis field. Of the 2759 publications retrieved, 1958 (71%) were published in 10 journals. These journals are listed in Table 1. ANNALS OF THE RHEUMATIC DISEASES published the greatest number of articles (653; 23.63%), followed by ARTHRITIS & RHEUMATOLOGY (329; 11.90%), and SEMINARS IN ARTHRITIS AND RHEUMATISM (301; 10.89%). Publications in these three journals accounted for 1283 (46.42%) of the total publications included in this study. The journal with the highest IF was ANNALS OF THE RHEUMATIC DISEASES, with an IF of 16.10 in 2020; this journal also contributed the largest number of articles on RA prognosis. The majority (80%) of RA prognosis-related articles were found in journals from the United States of America and the United Kingdom.
Table 1
Journal | Occurrence frequency | Proportion of frequency (%) | IF(2020) | Country | Publication frequency | Open Access |
ANNALS OF THE RHEUMATIC DISEASES | 653 | 23.63 | 16.10 | USA | Monthly | No |
ARTHRITIS AND RHEUMATOLOGY | 329 | 11.90 | 9.59 | USA | Monthly | No |
SEMINARS IN ARTHRITIS AND RHEUMATISM | 301 | 10.89 | 4.75 | USA | Bimonthly | No |
RHEUMATOLOGY | 220 | 7.96 | 5.61 | UK | Monthly | No |
JOURNAL OF RHEUMATOLOGY | 185 | 6.69 | 3.35 | Canada | Monthly | No |
VALUE IN HEALTH | 66 | 2.39 | 4.75 | USA | Bimonthly | No |
CLINICAL RHEUMATOLOGY | 58 | 2.10 | 2.39 | UK | Monthly | No |
ARTHRITIS RESEARCH ANDTHERAPY | 54 | 1.95 | 4.15 | UK | Monthly | Yes |
CLINICAL AND EXPERIMENTAL RHEUMATOLOGY | 50 | 1.81 | 3.32 | Italy | Bimonthly | No |
ARTHRITIS CARE AND RESEARCH | 46 | 1.66 | 4.06 | USA | Bimonthly | No |
Distribution of cited references
A total of the 29 052 cited references were counted; the top 10 are shown in Table 2. The most-cited paper, discussing the RA classification standards, was published by the American Rheumatism Association (ACR) in 1988, with 296 citations. The AAS of the co-cited article, the European League Against Rheumatism (EULAR)’s recommendations for RA management, published in 2013, had the top score of 492 and also ranked first in the h index.
Table 2
Top 10 co-cited references in RA prognosis
No. | Article Title | First Author | Year | Citation | Cluster | Link | Altmetric | h Index |
1 | The American-Rheumatism-Association 1987 Revised Criteria For The Classification Of Rheumatoid-Arthritis | ARNETT FC | 1988 | 296 | 2 | 1298 | 32 | 79 |
2 | Modified Disease-Activity Scores That Include 28-Joint Counts - Development And Validation In A Prospective Longitudinal-Study Of Patients With Rheumatoid-Arthritis | PREVOO MLL | 1995 | 176 | 4 | 958 | | 8 |
3 | Measurement Of Patient Outcome In Arthritis | FRIES JF | 1980 | 120 | 1 | 617 | 29 | 88 |
4 | The American-College-Of-Rheumatology Preliminary Core Set Of Disease-Activity Measures For Rheumatoid-Arthritis Clinical-Trials | FELSON DT | 1993 | 89 | 1 | 547 | 15 | 128 |
5 | 2010 Rheumatoid Arthritis Classification Criteria An American College Of Rheumatology/European League Against Rheumatism Collaborative Initiative | Aletaha D | 2010 | 146 | 4 | 515 | 91 | 74 |
6 | Treating Rheumatoid Arthritis To Target: Recommendations Of An International Task Force | Smolen JS | 2010 | 74 | 3 | 530 | 24 | 121 |
7 | The Premier Study - A Multicenter, Randomized, Double-Blind Clinical Trial Of Combination Therapy With Adalimumab Plus Methotrexate Versus Methotrexate Alone Or Adalimumab Alone In Patients With Early, Aggressive Rheumatoid Arthritis Who Had Not Had Previous Methotrexate Treatment | Breedveld FC | 2006 | 68 | 3 | 546 | 21 | 107 |
8 | EULAR Recommendations For The Management Of Rheumatoid Arthritis With Synthetic And Biological Disease-Modifying Antirheumatic Drugs: 2013 Update | Smolen JS | 2014 | 68 | 4 | 284 | 492 | 121 |
9 | Development And Validation Of The European League Against Rheumatism Response Criteria For Rheumatoid Arthritis - Comparison With The Preliminary American College Of Rheumatology And The World Health Organization International League Against Rheumatism Criteria | vanGestel AM | 1996 | 65 | 5 | 418 | 12 | 7 |
10 | Clinical And Radiographic Outcomes Of Four Different Treatment Strategies In Patients With Early Rheumatoid Arthritis (The Best Study) - A Randomized, Controlled Trial | Goekoop-Ruiterman YPM | 2005 | 62 | 3 | 546 | 44 | 24 |
10 | Infliximab And Methotrexate In The Treatment Of Rheumatoid Arthritis | Lipsky PE | 2000 | 62 | 1 | 401 | 16 | 115 |
Distribution of authors and co-authorship in research groups
Altogether, 8879 authors were involved in the included RA prognosis studies. The core authors (comprehensive index ≥ 1) are shown in Table 3. Of the core authors, Emery, P (115 publications) ranked first, followed by Strand, V (70 publications), and Keystone, E (69 publications). The information on author co-citations was also analyzed. Of the co-cited authors, Smolen, JS (606 co-citations) ranked first, followed by Wolfe, F (453 co-citations), and Aletaha, D (408 co-citations). In summary, Smolen, JS ranked first (4.75) in the comprehensive index, while Emery, P ranked first in the h index (121).
Table 3
Core authors in RA prognosis
No. | Author | Papers | Papers of first author | Cited article number | comprehensive index | h-index |
1 | Smolen JS | 38 | 9 | 606 | 4.75 | 121 |
2 | Emery P | 115 | 30 | 225 | 3.87 | 162 |
3 | Wolfe F | 21 | 15 | 453 | 3.39 | 115 |
4 | Strand V | 70 | 48 | 254 | 3.12 | 79 |
5 | Aletaha D | 22 | 6 | 392 | 3.02 | 74 |
6 | Pincus T | 14 | 5 | 408 | 2.95 | 100 |
7 | van der Heijde D | 54 | 10 | 190 | 2.37 | 145 |
8 | Combe B | 66 | 15 | 105 | 2.07 | 80 |
9 | Fleischmann R | 67 | 25 | 64 | 1.82 | 95 |
10 | Keystone E | 69 | 10 | 49 | 1.76 | 83 |
11 | Dougados M | 57 | 6 | 66 | 1.62 | 138 |
12 | Sokka T | 17 | 10 | 179 | 1.52 | 66 |
13 | Genovese MC | 34 | 12 | 110 | 1.43 | 67 |
14 | Scott DL | 16 | 2 | 159 | 1.37 | 12 |
15 | Young A | 37 | 1 | 91 | 1.37 | 38 |
16 | Keystone EC | 36 | 12 | 89 | 1.33 | 66 |
17 | Tanaka Y | 46 | 9 | 51 | 1.29 | 62 |
18 | Ostergaard M | 35 | 2 | 86 | 1.29 | 86 |
19 | Weinblatt ME | 29 | 3 | 105 | 1.29 | 78 |
20 | Curtis JR | 36 | 15 | 76 | 1.25 | 108 |
21 | Burmester GR | 42 | 3 | 56 | 1.24 | 114 |
22 | Boers M | 19 | 2 | 129 | 1.24 | 94 |
23 | Westhovens R | 43 | 6 | 50 | 1.23 | 62 |
24 | Kremer JM | 19 | 1 | 113 | 1.13 | 71 |
25 | Gossec L | 24 | 7 | 90 | 1.09 | 65 |
Collaborations between individuals, institutions, and countries, is critical for the success of most large-scale trials. Figure 3.A shows the network visualization of authors involved in research on RA prognosis. Thirteen groups included 122 authors, with the largest group consisting of 21 members centered on Michael Weinblatt. The highest co-cited author was Edward Keystone with 2844 co-citations, followed by Paul Emery (2578), and FC Breedveld (1461). Keystone and Haraoui, both Canadian scholars, appeared to work closely together, largely on medication policy and the use of drugs in a Canadian setting. Other authors, such as Breedveld, appear to focus more on their own research teams rather than collaborators. As shown in Fig. 3.B, these highly productive authors represent the backbone of recent research. Figure 4 indicates that most publications in the field were from the United States, followed by the United Kingdom, with the majority of Chinese publications dating from 2017 onwards.
Distribution of keyword hotspots
The clusters of similar keywords are shown in Fig. 5.A The 38 keywords are divided into four categories; each category is shown in a different color (red, blue, yellow, or green). Table 4 shows the keywords contained within each cluster. The clusters represent the features and trends in research into RA prognosis, as follows:
Table 4
Co-occurrence analysis of keywords
Cluster1 RED | Cluster2 GREEN | Cluster3 BLUE | Cluster4 YELLOW |
Rheumatoid Arthritis (566) | Methotrexate (182) | Prognosis (135) | Remission (95) |
Disease-activity (234) | Double-blind (114) | Disease (129) | Recommendations (77) |
Quality-of-life (96) | Therapy (106) | Follow-up (91) | Criteria (75) |
Disability (79) | Modifying antirheumatic drugs (92) | Mortality (93) | American-college (80) |
Validation (86) | Combination therapy (83) | Joint damage (56) | Management (59) |
Clinical-trials (58) | Etanercept (68) | Radiographic progression (56) | Classification (52) |
Fatigue (47) | Infliximab (56) | Damage (45) | |
Health-assessment questionnaire (47) | Adalimumab (49) | Risk (74) | |
Patient-reported outcomes (42) | Efficacy (58) | | |
Impact (46) | | | |
Pain (42) | | | |
Questionnaire (41) | | | |
Prevalence (51) | | | |
Validity (47) | | | |
Cluster 1 (shown in red) represents characteristics associated with RA assessment. The keywords include “disease-activity”, “quality of life”, “validation”, and “clinical trials”. In terms of “clinical trials”, for example, Japanese researchers proposed that alterations in anti-citrullinated peptide antibody (ACPA) titers are predictive of relapse in RA patients in remission14.
Cluster 2 (colored green) represents DMARDs. As also shown in Fig. 5.B, we found that although methotrexate appeared many times in the literature, most occurrences were concentrated around 2013. More recent studies have been concerned with etanercept, infliximab, adalimumab, and other TNF inhibitors.
Cluster 3 (colored blue) represents the identification of risk factors linked to RA prognosis. These include terms such as “joint damage” and “radiographic progression”. RA has a mortality rate about of 24%. Higher GSUS and CombUS scores have been associated with increased risk15.
Cluster 4 (colored yellow) represents RA classification and management. The keywords include “American college”, “management”, “criteria”, and “recommendations”. The EULAR recommendations have been generally accepted since 2013.