Objectives: Kidney transplantation is the gold standard kidney replacement therapy for patients with end-stage renal disease, prolonging the lifespan and improving quality of life of recipients by offering both emotional and psychological benefits. However, comorbid conditions, fear of rejection, drug side effects, and hospitalization can negatively affect health-related quality of life. Here, we performed a quantitative analysis of research addressing quality of life in kidney transplant recipients between 1987 and 2025.
Materials and Methods: We used descriptive and bibliometric analysis methods to analyze publications that addressed quality of life in kidney transplant recipients in the Web of Science Core Collection database. We used the VOSviewer software program to analyze publications by year, co-authorship networks; citations by author, country, and institution; author key words; bibliographic matching analysis of authors and networks of publications, and co-citation analysis of authors.
Results: From 816 publications identified during the analysis period, 743 were ultimately related to quality of life in kidney transplant recipients. According to publication year, the highest concentration was observed in 2025 (88 works), 2024 (69 works), and 2023 (64 works). Authors Johnathan C. Craig, Stefan P. Berger, and Stephan J. L. Bakker had 24, 21, and 21 publications respectively, with the University of Groningen being the most active institution (41 publications). Most publications were from the United States (n = 202), The Netherlands (n = 70), and Italy (n = 69). Transplantation Proceedings had the most publications (n = 67). Most publications were in English. The most frequently used author key words were “kidney transplantation” (n = 252), “quality of life” (n = 105), and “kidney transplant” (n = 89).
Conclusions: Our results demonstrated the increasing interest among researchers in studying quality of life in kidney transplant recipients and revealed the diversity of issues and perspectives related to this field. Key words: Kidney transplantation, Literature analysis, Bibliometrics analysis, Renal transplant, Quality of life

Introduction
Kidney transplantation is the gold standard kidney replacement therapy for patients with end-stage renal disease.¹ Kidney transplants constitute the largest proportion of solid-organ transplants compared with liver, heart, and lung transplants.² Kidney transplant prolongs the recipient’s lifespan and improves their quality of life by offering both emotional and psychological benefits.³ After transplant, the functional and physical aspects of health-related quality of life (QoL) improve; however, a number of factors, such as comorbidities, fear of rejection, drug side effects, and hospitalization, can negatively affect health-related quality of life.^4,5 Kidney transplant recipients may also have a lower quality of life and experience challenges in terms of physical well-being compared with the general population.⁶ Bibliometrics is a literature analysis methodology that evaluates the publication output and status of a particular research area using quantitative and qualitative lenses.⁷ VOSviewer was developed by Nees Jan van Eck and Ludo Waltman, researchers at the Centre for Science and Technology Studies at Leiden University. VOSviewer is a software tool used to create and visualize bibliometric networks. These networks can include, for example, journals, researchers, or individual publications, and can be constructed based on citation, bibliographic matching, co-citation, or co-authorship relationships. VOSviewer also offers text mining functionality that can be used to create and visualize co-occurrence networks of key terms extracted from the scientific literature.⁸ In this context, the aim of this study was to map and quantitatively analyze research addressing quality of life in kidney transplant recipients. We aimed to answer the following: the distribution of publications in the field of kidney transplant recipients and quality of life over the years; the structure of the co-authorship network; which author, country, and institution stand out in this field; how the author’s key words reflect research themes in the literature; and whether the analysis reveals the literature’s theoretical and intellectual structure.

Materials and Methods
Since the research data was based on published studies, ethical committee approval was not required. For bibliometric data, we searched the Web of Science Core Collection (WoS) database on publications from 1987 through 2025 using the key words “kidney transplant recipients” and “quality of life” with the selection of “all fields” to yield 816 publications on February 13, 2026. The indexes in the database were limited to “Science Citation Index Expanded,” “Social Sciences Citation Index,” and “Emerging Sources Citation Index.” Inclusion criteria were limited to WoS category, publication type (article and review article), publication language (including all languages), publishing institutions, countries (including all institutions and countries), citation subjects, journals, authors, and publications between 1987 and 2025. As a result of these limitations, 743 articles obtained from the WoS database formed the dataset for this study.

Data analysis
We transferred bibliographic data from the Bibliometrix software package (version 4.4.3) to VOSviewer software (version 1.6.20) for bibliometric mapping and network analysis. We used VOSviewer to create national collaboration networks, author collaboration networks, institutional collaboration networks, and document co-citation relationships. The analysis included distribution of publications by year; co-authorship networks of authors; citation analyses by author, country, and institution; co-occurrence networks based on author key words; bibliographic matching analyses of publications; bibliographic matching networks of authors; and co-citation networks of authors. Co-authorship and key word networks were constructed based on their frequency of co-occurrence. Thematic and collaboration clusters within the network structures were identified using VOSviewer’s clustering algorithm. In the maps, node size reflected the productivity of the relevant unit, and connection thickness reflected the strength of the relationship between units.

Results
Among 743 articles on quality of life of kidney transplant recipients, categorized by year from 1987 to 2025, 585 were research articles and 158 were review articles. Figure 1 shows the distribution of publications by year. In terms of language, most publications were in English (n = 729), followed by German (n = 4), French (n = 4), Russian (n = 2), Korean (n = 1), Portuguese (n = 1), Spanish (n = 1), and Turkish (n = 1).

Co-authorship of authors
In the co-authorship analysis of the authors, a network map was created by defining the criteria of at least 2 publications and at least 2 citations to identify the most related and collaborating authors. The analysis, conducted on 352 interconnected units, revealed 17 clusters, 1996 connections, and total connection strength of 3375. The top 3 authors with the highest total connection strength were Johnathan C. Craig (24 publications, 1784 citations, and 168 total connection strength), Stephan J. L. Bakker (21 publications, 285 citations, and 143 total connection strength), and Stefan P. Berger (21 publications, 220 citations, and 141 total connection strength). The co-authorship network is shown in Figure 2.

Citation of authors
A network map for author citation analysis was created using the criteria of at least 2 publications and at least 2 citations to identify citation networks. Analysis of 544 interconnected units revealed 14 clusters, 10 520 connections, and total connection strength of 18 802. The top 3 authors with the most citations were Bertram L. Kasiske (n = 2123 citations), Kai-uwe Eckardt (n = 2045 citations), and Jonathan C. Craig (n = 1784 citations). In terms of total connection strength, the top 3 authors were Istvan Musci (n = 785), Jonathan C. Craig (n = 677), and Stefan J. L. Berger (n = 629). The citation ties of the authors are shown in Figure 3.

Citation of countries
To create a network map of citations received by publications according to their country of origin, an analysis was conducted on 51 observation units with interrelationships, based on the criterion of a country publishing at least 2 works and receiving 2 citations. Analyses identified 8 clusters, 438 connections, and total connection strength of 2703. The countries with the most citations were the United States (5881 citations), Australia (2987 citations), and Italy (2225 citations). In terms of total connection strength, the United States (860), The Netherlands (449), and Canada (449) ranked in the top 3. In terms of the number of publications, ranking showed the United States with 202 publications, The Netherlands with 70 publications, and Italy with 69 publications. The citation relationships of the countries are shown in Figure 4.

Citation of institutions
To create a network map of inter-institutional citations, an analysis was conducted on 364 observation units with interrelationships, based on the criterion of an institution publishing at least 2 works and receiving 2 citations. The University of Groningen (41 works) and the University of Sydney (39 works) were represented by the most works, and institutions with the most cited publications were the University of Sydney (2554 citations), the University of Bari (1300 citations), and the University of Alberta (1166 citations). In total, 14 clusters, 5103 connections, and total connection strength of 9112 were identified. The citation relationships of the institutions are shown in Figure 5.

Co-occurrence of author key words
Before the co-occurrence analysis, the criterion of key words appearing at least twice was applied. Based on this threshold, 297 author key words were included in the analysis, with key words grouped under 21 different clusters. Analysis identified 1871 connections between the key words, and the total connection strength was calculated as 2674. The findings indicated that the research area has a multi-cluster structure with intense conceptual interaction. The 3 most frequently used key words were “kidney transplantation” (252 repetitions), “quality of life” (105 repetitions), and “kidney transplant” (89 repetitions). In terms of total connection strength, the strongest expressions were again “kidney transplantation” (n = 633), “quality of life” (n = 281), and “kidney transplant” (n = 206). The most frequently used author key word connections are shown in Figure 6.

Bibliographic coupling of documents
Bibliographic matching refers to the situation where a common work is cited by 2 independent sources. Based on an analysis of 599 documents selected with the criterion of having at least 2 citations and having links between them, 13 clusters, 21 411 links, and total link strength of 37 719 were obtained. The publications with the most bibliographic matches were Eckardt (2009)⁹ with 2030 citations and Palmer and colleagues (2013)¹⁰ with 667 citations. The documents with the highest total link strength were Karpe and colleagues (2017)¹¹ with 2010 links, Haller and colleagues (2017)¹² with 1392 links, and Pascual and colleagues (2009)¹³ with 1127 links. The bibliographic matching relationships of the documents are shown in Figure 7.

Bibliographic coupling of authors
An analysis of 604 related units, selected based on the criterion of having published at least 2 works and received 2 citations, revealed 14 clusters, 90 248 connections, and total link strength of 711 714. The authors with the most bibliographic matches were Bertram L. Kasiske with 2123 citations (3714 link strength), Kai-Uwe Eckardt with 2045 citations (4583 link strength), and Jonathan C. Craig with 1784 citations (22 474 link strength). The bibliographic match relationships of the authors are shown in Figure 8.

Co-citation of cited authors
Different sources cited in a publication are called co-citations. Based on an analysis of 423 units with a minimum of 10 citations, 5 clusters, 27 384 links, and total link strength of 112 007 were identified. The authors with the most co-citations were Bertram L. Kasiske (n = 119), Miklos Z. Molnar (n = 109), and Robert A. Wolfe (n = 107). The authors with the highest total link strength were Bertram L. Kasiske (5238 link strength), Klemens Budde (4039 link strength), and Henrik Ekberg (2695 link strength). The co-citations between cited authors are shown in Figure 9.

Discussion
This study used bibliometric analysis to examine research on quality of life in kidney transplant recipients between 1987 and 2025, with 743 studies selected from the WoS database for the analysis. VOSviewer was used to reveal the growth trajectory; co-authorship networks; citation analysis of authors, countries, and institutions; bibliographic matching analysis of authors; bibliographic matching networks of publications; and co-citation analysis of authors and most frequently used key words in the studies. In recent years, advances in surgical techniques and use of more effective immunosuppressive agents have led to improvements in patient survival rates.¹⁴ This study highlighted the growing importance of the concept of quality of life in kidney transplant recipients. Furthermore, this study is expected to guide future research by presenting bibliometric analysis as a methodological tool for understanding the concept of quality of life in kidney transplant recipients. Through VOSviewer software, we were able to visualize a literature review on quality of life in kidney transplant recipients, revealing relationships between international collaborations and key concepts. The more articles published in a field, the faster the pace of scientific progress.¹⁵ Our results reflected the increasing interest in this topic, with studies on quality of life in kidney transplant recipients increasing in recent years, and the highest number of publications recorded in 2025. Citation numbers reflect the importance of individuals, teams, and journals in a field.¹⁵ In the co-authorship analysis of the authors, the findings revealed that the field is clustered around specific research groups, and some authors stand out significantly in the collaborative network. Our study showed that some authors with high citation rates in the literature have more theoretical/conceptual impact, whereas others have a more active role in the formation of collaborative networks. This divergence reveals that the field follows a multilayered development process in terms of both intellectual and social structure. The total number of publications is a significant indicator of a country’s productivity and output.¹⁶ Our findings in the citation analysis showed that countries had differences in terms of productivity, citation impact, and collaboration intensity. The fact that the countries with the most citations were the United States, Australia, and Italy indicated that these countries have a high impact on the literature. The United States, the Netherlands, and Canada were central to international research collaborations in terms of total link strength. The United States significantly influenced the number of publications and citations due to its established academic systems, funding support, and international collaborations.¹⁷ The frequency of citations of an article allows for measuring the impact of an article over time.¹⁸ Our findings showed that productivity and citation impact did not completely overlap among institutions. This situation reveals that institutional performance should be evaluated not only by the number of publications but also by the citation impact. The fact that “kidney transplantation,” “quality of life,” and “kidney transplant” were the 3 most frequently used key words in the author’s key word analysis indicated that kidney transplantation and quality of life are key topics of intense interest to researchers and frequently discussed in the literature. These 3 key words also stand out as having the strongest relationship network in terms of total link strength. The findings showed that the research area is clustered around certain core concepts and that the conceptual structure is shaped around these main themes. The simultaneous appearance and sudden increases of key words in the literature highlight research focus over time.¹⁹ Our findings showed that the level of bibliographic matching and the density of connections within the network were not always parallel. This suggested that, although some publications exhibit strong thematic matches in the literature, others have a more central and relational role in the network structure. Our findings noted substantial differences between the level of bibliographic matching and overall connection strength. This finding indicated that some authors, in addition to having a high number of matches, establish much broader and denser connection networks in the literature, playing a decisive role in the intellectual structure of the field. The findings also revealed that some authors may have more limited connection density with other authors in the network despite frequent co-citations in the literature, whereas other authors, despite having fewer co-citations, play a critical role at the center of the network.

Limitations
Our study had some limitations. First, this study only included publications from the WoS Core Collection database. Second, only articles and review articles were included.

Conclusions
This bibliometric analysis comprehensively evaluated the current literature on the quality of life of kidney transplant recipients, revealing trends in research in this area. Our study noted a substantial upward trend in the literature with regard to publications on the quality of life of kidney transplant recipients in recent years. This finding may reflect the increasing awareness of quality of life in kidney transplant recipients and efforts to better understand the effects of posttransplant quality of life on patient outcomes. This research can serve as a resource for studies on the quality of life in kidney transplant recipients.