Impact of COVID‐19 on abdominal organ transplantation: A bibliometric analysis

Abdominal solid organ transplant (SOT) programs have been hit hard by the COVID‐19 pandemic, which was officially declared as such on March 11, 2020. Over two years, the tightening and softening of limitations in response to the “waves” of infection and COVID‐19 fluctuations have provided distinct issues for waitlisted patients, transplant recipients, and transplant organizations.

posed unique challenges for waitlisted patients, transplant recipients, and transplant programs. 6 However, the regional and chronological impact of COVID-19 on transplantation has varied. 7 The hundreds of articles on the impact of COVID-19 on transplantation include a wide range of subjects and issues. In order to make recommendations to clinical staff responsible for caring for organ transplant recipients during the COVID-19 pandemic, these publications investigated the clinical aspects of COVID-19 infection on recipients and patients on waiting lists, as well as vaccine guidance, 8,9 immunosuppressant usage and potential drug interactions, immune responses to COVID-19, and COVID-19 diagnostic and treatment options. 10 Later articles looked into the consequences of the COVID-19 pandemic on transplantation by reviewing transplant activity and adjustments to transplant centers' procedures during the pandemic because of its impact on transportation, donor availability, and the resources that had to be reallocated to fulfill the most urgent needs. 9,[11][12][13] The pandemic has provided invaluable lessons; rapid research clearances, streamlined registry data links, and the expedited publication of open-access papers have contributed to the rapid distribution of new evidence. 14 It is recognized that transplant teams at regional, national, and international levels collaborated well to support staff and patients.
The primary analytical focuses of this study, which were achieved through bibliometric analysis, were the productivity and collaboration of countries, organizations, and authors during the pandemic and the distribution of publishing outputs. By conducting this research, we could identify the literature that has had the most significant influence on this topic to date, thereby enhancing the understanding of how COVID-19 has impacted the transplantation community.

Data analysis
The number of citations served as the basis for all analyses. Using VOSviewer version 1.6.18 and Microsoft Excel, we analyzed annual trends, countries, institutions, authors, journals, keywords, and articles and generated tables and figures. The included/excluded studies were presented using a flowchart.
The most frequently occurring keywords were studied by limiting them to a minimum of 250 occurrences. In the keyword analysis, we manually removed words that implied the study design, such as "clinical trial," "retrospective study," and "case-control," and redundant words such as "human," "male," "female," and "adult." We also removed words like "COVID-19" and "SARS-CoV-2" to reduce redundancy. We ana-

Included studies
Of the 1256 search results, we included 1251 studies. Five studies were excluded because of missing information, and one study was excluded due to its 2023 prerelease date. In terms of the document type, 846 studies were articles, 79 studies were reviews, and the rest were conference papers, editorials, errata, letters, notes, and short surveys (n = 925) ( Figure S1). In total, the included studies were cited 14,738 times, with a mean (SD) of 17.0 (36.1) citations per study.

Annual trends
The studies were published from 2020 to 2022, reflecting the pan-

Institutions-according to number of publications Country Publications Citations
Johns

Countries
We found that most of the publications were undertaken by institutes

Institutions
In terms of the total number of publications, the top three contribut- France had the following highest numbers of citations (Table 1).  Table S3. Figure S2 demonstrates a cluster map of some of the most collaborative authors.

Journals
Most  (Table S4). Figure 2 shows the top-cited journals and their interconnections between the clusters.

Top-cited articles
The top 10 most-cited articles are listed in Table 2

Keywords
The top 20 most occurring keywords on transplantation and COVID-19 are shown in Table S5. Ten of them occurred over 300 times each: "kidney transplantation," "graft recipient," "immunosuppressive treatment," "tacrolimus," "transplant recipients," "adverse event," "liver transplantation," "kidney graft," "mycophenolate mofetil," and "pandemics." Figure S3 shows the most occurring keywords across the years as a cluster visualization.  6,7,15 The need to conserve healthcare resources whenever possible and the desire to avoid COVID-19-related morbidity and mortality in immunocompromised patients deemed to be at a higher risk for severe disease may have been the most important factors influencing this decline. 12,13 Since the announcement of the first case, the number of articles This may have affected how often the articles were quoted.

CONCLUSION
This review was written to supplement existing research on abdom-

CONFLICT OF INTEREST STATEMENT
The authors declare no conflict of interest.