A bibliometric and visual analysis of neutrophil to lymphocyte ratio from 2004 to 2023

BackgroundThe Neutrophil to lymphocyte ratio (NLR) has emerged as a pivotal biomarker in the fields of inflammation and immunity research. NLR, calculated from routine blood counts, reflects the balance between neutrophil-driven innate immunity and lymphocyte-mediated adaptive responses. In recent decades, a growing body of research has underscored the application of this field across diverse medical disciplines, including oncology, cardiology, immunology, and other areas of medicine. However, there is a paucity of comprehensive studies that objectively map the evolving landscape, hotspots, and research frontiers of global NLR studies. MethodsA comprehensive search was conducted using the Web of Science Core Collection to identify articles and reviews related to NLR from 2004 to 2023. A robust bibliometric approach was employed, utilizing tools such as VOSviewer, CiteSpace, and Bibliometrix (R-tool for R Studio). Analyses were focused on publication outputs, country/institutional collaborations, journal and author productivity, and keyword co-occurrence. This approach provides both quantitative and qualitative perspectives on the NLR field. ResultsThe bibliometric review under consideration included a total of 14,877 publications, which indicates a marked upward trend in annual publications. The United States and China contributed the most papers and maintained leading positions in international collaborations and citation influence. A close examination of the most prolific journals in the field, including Frontiers in Oncology, Medicine, and PLOS One, has revealed their role as pivotal dissemination outlets. A comprehensive analysis of the literature revealed that keywords pertaining to oncology, immunotherapy, inflammation, prognosis, and clinical outcome exhibited a marked prevalence in research themes related to NLR. Of particular note is the escalating convergence of these themes with those concerning cancer immunotherapy, cardiovascular risk, and systemic inflammatory response syndromes. Co-citation and cluster analyses revealed an increasing connection between research on the nucleotide-binding leucine-rich repeat (NLR) proteins and emerging fields, including tumor immunology, metabolic disease, and personalized medicine. Network mapping revealed an increase in intercontinental collaborations and identified key researchers who are influencing the discipline. ConclusionsThis is the inaugural bibliometric and visual analysis to methodically map the global research landscape of neutrophil-to-lymphocyte ratio. The study reveals a thriving and multidisciplinary research landscape, with significant concentrations in oncology and immunology, as well as noteworthy advancements into emerging domains such as immunotherapy and precision medicine. By unveiling collaboration patterns, identifying leading contributors, and examining keyword trends, this work offers indispensable guidance for scholars seeking to identify impactful research topics and establish strategic partnerships. These insights not only illuminate the current status of NLR research but also forecast its promising directions, inviting further exploration and cross-disciplinary innovation in the years ahead.