Mapping Two Decades of GLP-1 Diabetes Research: A Landmark Bibliometric Analysis

Few drug classes in modern medicine have climbed as fast as the GLP-1 receptor agonists, the incretin-mimicking therapies that have reshaped the treatment of type 2 diabetes and, more recently, obesity and kidney disease. Yet despite their clinical prominence, no one had systematically mapped how the research literature on these drugs actually grew, who produced it, and how its themes shifted over two decades. A new bibliometric analysis published in Health Science Reports fills that gap, tracing 3,736 original research articles published between 2004 and 2025 and revealing a field that has expanded more than eightyfold while pivoting from glucose control toward cardiovascular, renal and weight-related outcomes.

The scale of the underlying clinical problem explains the intensity of the research effort. In 2024, an estimated 588.7 million adults worldwide were living with diabetes, more than 90 percent of them with the type 2 form, and prevalence is projected to reach 852.5 million by 2050. Type 2 diabetes is not merely a disorder of blood sugar: cardiovascular disease was reported in roughly a third of patients in a 13-country study, diabetic kidney disease affects up to 35 percent of patients and remains a leading cause of end-stage renal disease, and the frequent coexistence of obesity accelerates disease progression. These realities have pushed therapeutic priorities beyond short-term glycemic targets toward durable metabolic control, reduction of cardiovascular and renal risk, weight management and long-term treatment sustainability.

To chart the field’s development, the researchers searched the Web of Science Core Collection from January 2004 to December 2025, using a strategy that combined drug-class terms, generic and brand names of individual agents and disease-specific terms refined with proximity operators. Only original research articles in English were included, and two investigators independently screened all records against a predefined eligibility manual. The team then cleaned and standardized the data meticulously: country and institutional affiliations were harmonized, author keywords were consolidated across spelling and synonym variants, and drug names were standardized at two levels, merging formulations of the same agent for co-occurrence analyses while retaining regimen-level terms such as oral semaglutide for timeline and burst analyses. VOSviewer, CiteSpace and R handled the network construction, burst detection and statistical processing, and an independent PubMed search confirmed that more than 97 percent of the most-cited Web of Science articles were recoverable across databases.

The headline finding is explosive growth. Annual output rose from just 7 articles in 2004 to 589 in 2025. Studies restricted to selective GLP-1 receptor agonists accounted for 94.86 percent of the entire corpus, but studies involving GLP-1-based multi-receptor agonists, which engage additional metabolic hormone receptors, first appeared in 2020 and by 2025 together with mixed comparative studies made up 14.09 percent of that year’s output. The subject-category breakdown shows a literature spanning far beyond endocrinology and metabolism, which dominated at 55.03 percent, into pharmacology, general medicine, experimental medicine and cardiac and cardiovascular systems, reflecting the drugs’ widening clinical footprint.

Geographically, 80 countries and regions contributed, but the distribution was strikingly unequal. Under fractional counting, the ten most productive countries accounted for 79.01 percent of output, with the United States and China alone contributing 43.11 percent, and a country-level Gini coefficient of 0.837 signaled profound inequality. The United States led on nearly every measure, with 1,558 articles, 112,863 citations and the strongest collaboration links, while the United Kingdom and Denmark achieved higher citations per publication than the United States despite smaller outputs. China ranked second in publication volume but only tenth in total collaboration strength, and its multiple-country publication proportion was markedly lower than those of Germany, the United Kingdom, Canada and the Netherlands, illustrating that output, citation influence and collaboration intensity are distinct dimensions of national research performance.

The institutional analysis revealed a research ecosystem built around both pharmaceutical and academic hubs. Novo Nordisk and Eli Lilly ranked first and second in both full-counted publication output and total citations, with 426 and 343 articles and 43,640 and 32,211 citations respectively, and they remained the top two contributors even after fractional allocation of multi-institutional papers. Among academic centers, the University of Toronto, the University of Texas Southwestern Medical Center and the University of North Carolina stood out for citation impact. Institutional output followed a long-tailed distribution with a Gini coefficient of 0.682, yet the top ten institutions captured only 11.26 percent of fractional output, meaning no small group monopolized the field. At the author level, dispersion was even greater: the ten most productive researchers, led by Julio Rosenstock with 75 articles and a dataset-specific h-index of 41, accounted for just 1.62 percent of total fractional output, and 82 of 83 threshold-eligible authors formed a single connected co-authorship network of ten clusters.

The thematic evolution tells perhaps the most compelling story. Keyword co-occurrence analysis grouped the 100 most frequent author keywords into six clusters spanning incretin biology, individual therapies, glycemic management, obesity, cardiorenal complications and real-world evaluation. Timeline and burst analyses then revealed four developmental stages: a foundational period from 2004 to 2008 centered on incretin physiology and early exenatide trials; a therapeutic expansion phase from 2009 to 2015 dominated by liraglutide and the LEAD program; a cardiovascular-outcomes period from 2016 to 2020 shaped by landmark trials within a regulatory environment created by the 2008 US Food and Drug Administration cardiovascular-risk guidance; and, from 2021 onward, a phase of cardiovascular-kidney-metabolic integration featuring semaglutide, the dual GIP/GLP-1 agonist tirzepatide, obesity, chronic kidney disease, oral formulations and real-world evidence. Burst detection captured this shift quantitatively, with the strongest keyword burst belonging to GLP-1 itself from 2008 to 2018, and recent bursts for chronic kidney disease, fixed-ratio combination therapy and oral semaglutide extending through 2025.

Citation analysis confirmed which individual studies drove these transitions. When citations were normalized within publication year to remove the advantage of older papers, the LEADER trial of liraglutide by Marso and colleagues ranked first, with 6,891 total citations and a normalized score of 62.94, meaning it received nearly 63 times the mean citations of publications from the same year. The 2024 trial of semaglutide in patients with type 2 diabetes and chronic kidney disease ranked second despite its short citation window, followed by the REWIND dulaglutide trial and the head-to-head comparison of tirzepatide with semaglutide. Six of the top ten appeared in the New England Journal of Medicine and four in The Lancet. Among cited references, LEADER also produced the strongest citation burst, and the analysis showed influence migrating from early exenatide trials through the LEAD program and ADA/EASD consensus statements toward cardiorenal outcome trials and clinical guidance, with seven references still bursting through 2025.

The journal landscape added a further layer of nuance. The 3,736 articles were spread across 627 journals, but a recognizable specialty core emerged, led by Diabetes, Obesity and Metabolism with 494 articles, followed by Diabetes Therapy and Diabetes Care. Co-citation rankings told a different story: Diabetes Care was the most co-cited journal, but the New England Journal of Medicine and The Lancet were highly co-cited despite publishing few of the included articles, suggesting that landmark trials achieve their widest influence through general medical journals while the cumulative development of the evidence remains anchored in specialist outlets. Dual-map overlay analysis showed clinically oriented articles drawing on both molecular-biological and health-services literature, consistent with bidirectional translation between incretin biology, therapeutic development and outcomes research.

The authors are careful about what these bibliometric signals do and do not mean. Citation counts measure scholarly attention, not methodological quality or clinical benefit, and institutional prominence based on affiliations should not be read as evidence of funding involvement or commercial influence. They also note that the evidence base remains uneven: multi-receptor agonists other than tirzepatide, such as retatrutide and survodutide, have been studied mainly for short- to intermediate-term glycemic and weight outcomes, real-world data document substantial discontinuation and reinitiation, patient-experience research is strikingly thin, and racial, ethnic and socioeconomic disparities in trial participation and drug use persist. Combined with the geographic concentration documented here, these gaps suggest that the next phase of GLP-1 research will need to extend beyond efficacy and cardiovascular outcomes into long-term effectiveness, treatment persistence, equity and the populations and care settings that the current literature has largely left behind.

Subject of Research: Bibliometric analysis of research on GLP-1 receptor agonists and GLP-1-based multi-receptor agonists in type 2 diabetes mellitus

Article Title: Global Landscape and Thematic Evolution of Selective GLP‐1 Receptor Agonists and GLP‐1–Based Multi‐Receptor Agonists in Type 2 Diabetes Mellitus: A Bibliometric Analysis

Article References: Wang, Y., Liu, Z., Wang, S., Lv, C., El‐Seedi, H. R., Khalifa, S. A. M., & Wang, H. (2026). Global Landscape and Thematic Evolution of Selective GLP ‐1 Receptor Agonists and GLP ‐1–Based Multi‐Receptor Agonists in Type 2 Diabetes Mellitus: A Bibliometric Analysis. Endocrinology, Diabetes & Metabolism, 9(6), Article e70351. https://doi.org/10.1002/edm2.70351

Image Credits: AI Generated

DOI: 10.1002/edm2.70351

Keywords: GLP-1 receptor agonists, type 2 diabetes, bibliometrics, semaglutide, tirzepatide, liraglutide, cardiovascular outcomes, chronic kidney disease, obesity, incretin biology, research collaboration, citation analysis