Inflammatory Bowel Disease (IBD) research in Spain has expanded considerably in recent decades; however, no structured evaluation has comprehensively assessed its scientific production or its representation at major international congresses. This study aimed to provide a descriptive overview of recent Spanish contributions to clinical, translational, and basic inflammatory bowel disease research, and to analyse scientific leadership, regional distribution, methodological approaches, research topics, and gender representation.
Material and methodsPublications from 2020 to 2024 were systematically retrieved from PubMed and classified according to study type, research topic, methodology, journal quartile ranking, and authorship characteristics. Accepted communications presented at the European Crohn's and Colitis Organisation congresses between 2019 and 2024 were also evaluated regarding study type, presentation format, scientific leadership, gender of the last author, and regional origin.
ResultsA total of 1361 Spanish scientific contributions were identified. Clinical research represented 61.3% (n=834) of publications, whereas basic and translational studies accounted for 38.7% (n=527) of the total output. 84.5% (n=1150) of publications were published in Quartile 1 or 2 journals, and 30.6% (n=291) of Quartile 1 articles appeared in top-decile journals. Scientific activity was predominantly concentrated in Catalonia and Madrid. Advanced experimental methodologies were frequently employed in basic and translational research. Across congress communications, 638 abstracts were identified, with Spain contributing 8.5–12.4% of total accepted presentations (n=80–126 abstracts annually). Women were more frequently represented in leadership roles in basic and translational research than in clinical studies.
ConclusionThe current landscape of IBD research in Spain is characterised by sustained scientific activity, a broad spectrum of clinical, translational and basic research, and extensive international collaboration, despite marked regional differences in research productivity and persistent gender disparities in leadership.
La investigación en enfermedad inflamatoria intestinal (EII) en España ha experimentado una expansión en las últimas décadas, sin embargo, no se ha realizado una evaluación estructurada de su producción científica global ni de su presencia en los principales congresos internacionales. Este estudio tiene como objetivo proporcionar una visión descriptiva de las contribuciones españolas recientes en investigación clínica, traslacional y básica, así como analizar el liderazgo científico, la distribución regional, los enfoques metodológicos, las áreas temáticas y género del último autor.
Materiales y métodosLas publicaciones correspondientes al periodo 2020–2024 se obtuvieron de forma sistemática a partir de PubMed y se clasificaron según el tipo de estudio, temática, metodología, impacto de la revista y características de autoría. Las comunicaciones aceptadas en los congresos de la European Crohn's and Colitis Organisation entre 2019 y 2024 se evaluaron en función del tipo de estudio, formato de presentación, liderazgo científico, género del último autor y la distribución regional.
ResultadosSe identificaron un total de 1.361 contribuciones españolas. La investigación clínica representó el 61,3% (n=834) de las publicaciones, mientras que los estudios básicos y traslacionales constituyeron el 38,7% (n=527) de la producción total. El 84,5% (n=1.150) de las publicaciones se realizaron en revistas situadas en los cuartiles 1 o 2, y el 30,6% (n=291) de los artículos publicados en revistas de cuartil 1 aparecieron en revistas pertenecientes al primer decil. La actividad científica se concentró principalmente en Cataluña y Madrid. Las técnicas experimentales avanzadas se utilizaron con frecuencia en la investigación básica y traslacional. En las comunicaciones a congresos se identificaron 638 resúmenes, con una contribución española de entre el 8,5% y el 12,4% del total de presentaciones (n=80–126 resúmenes anuales). El liderazgo de las mujeres fue más frecuente en la investigación básica y traslacional que en la investigación clínica.
ConclusiónEl panorama actual de la investigación sobre la EII en España se caracteriza por una actividad científica sostenida, un amplio espectro de investigación clínica, traslacional y básica, y una extensa colaboración internacional, a pesar de marcadas diferencias regionales en la productividad investigadora y persistentes desigualdades de género en los puestos de liderazgo.
The contribution of Spanish research to inflammatory bowel disease (IBD) has expanded substantially over recent decades. Early epidemiological studies in Galicia and central Spain1–3 established baseline prevalence estimates and clinical patterns, laying the foundations for subsequent multicentre registries and nationwide investigations. Over time, these advances contributed to the optimization of therapeutic strategies for IBD management.4,5 In parallel, continued clinical research has progressively improved therapeutic approaches for IBD management. Experimental work on inflammatory mediators and nutritional interventions in colitis models6–8 also contributed to advances in IBD pathophysiology and management.
Since the 2000s, Spain has experienced a marked rise in IBD incidence, reaching rates comparable to Northern Europe,9 alongside the consolidation of a multidisciplinary research community. Translational initiatives, including adipose-derived mesenchymal stem cells for complex perianal fistulas, progressed to regulated products and phase III clinical trials.10–13 Spanish groups have also contributed to microbiome research, nutrition, and immune modulation, reinforcing Spain's role in mechanism-oriented IBD research.14
The European Crohn's and Colitis Organisation15 (ECCO) Congress is a major international platform to evaluate scientific activity and leadership. Spain consistently ranks among the most represented countries,16 yet no systematic assessment has evaluated its contributions across congresses and peer-reviewed publications. This study aims to provide a descriptive overview of IBD research conducted by Spanish investigators through analysis of ECCO abstracts (2019–2024) and publications (2020–2024), with emphasis on basic and translational research.
Material and methodsSelection of PubMed publicationsSearches were conducted in PubMed15 (National Library of Medicine, Washington, DC, USA) in October 2024. The exact search query used was: ((((((((((ibd) OR (inflammatory bowel disease)) OR (crohn's disease)) OR (ulcerative colitis))))) OR (microscopic colitis)) OR (collagenous colitis)) OR (lymphocytic colitis)) AND (spain[Affiliation]). The search was restricted to publications from 2020 to 2024, and all records retrieved during this period were included in the bibliometric analysis. Microscopic colitis, including lymphocytic and collagenous subtypes, were included as moderate IBD forms that are increasingly recognized in scientific societies of the field. Yet, studies retrieved for microscopic colitis accounted minimally to the general IBD research in Spain (1.28%, n=21/1641).
Eligible documents included review articles, systematic reviews, meta-analyses, original research, and clinical trials. Letters, opinion pieces, case reports, protocols, guidelines, articles without full text, publications without Spanish contributions, and non-IBD studies were excluded. Screening was performed manually using titles and abstracts to remove duplicates and non-relevant records (Fig. 1).
Global IBD scientific output was estimated through an additional PubMed search using the same keywords without affiliation filters for each year (2020–2024).
Publications were classified according to last author affiliation and gender, study model (patient-based or not), article type (original or review), and research focus (pathophysiology, treatment, diagnosis, epidemiology, microbiota, comorbidities, or nutrition). Author gender was assigned based on the first name of the last author. In cases of uncertainty, publicly available institutional information was consulted whenever possible.
Articles were grouped into clinical research (studies involving patients, cohorts, registries, or healthcare outcomes) and basic/translational research (mechanistic, molecular, genetic, microbiological, or immunological studies conducted in vitro, in animal models, or using human-derived samples).
Within original articles, non-clinical studies were further classified as basic research (mechanistic studies performed in vitro, in animal models, or using human biological samples without correlation with clinical phenotypes or outcomes) or translational research (studies integrating biological mechanisms with clinical phenotypes, disease behaviour, prognosis, or treatment response, with the aim of bridging mechanistic findings and clinical application).
Original studies were also categorized by methodological approach as conventional techniques (e.g., histology, ELISA, qPCR, Western blotting, animal models, or microbial culture), advanced techniques (e.g., next-generation sequencing, multi-omics, single-cell analysis, organoids, or advanced imaging), or ex vivo analyses using human samples, which were prioritized when combined approaches were applied.
The classification process was performed by ten investigators from different Spanish research centres with expertise in basic and translational IBD research. Publications and abstracts were manually reviewed and assigned to predefined categories according to study type, research topic, and methodological approach. Cases of uncertainty were discussed collectively and resolved by consensus among the investigators.
Selected studies were assessed according to journal quartile ranking and impact factor based on the 2023 Journal Citation Reports.17
Selection of European Crohn's and Colitis Organisation (ECCO) conference abstractsAbstracts from ECCO congresses (2019–2024) authored by researchers with Spanish affiliation were retrieved from the ECCO database. Selection and classification followed the same criteria as peer-reviewed publications, including research type (basic, translational, clinical), presentation format (poster or oral/digital oral), and thematic content (Fig. 1).
Population referencePopulation data were obtained from the Instituto Nacional de Estadística (INE, Spain) for 2019 and used as the demographic reference.
Statistical analysis and graphical generationDescriptive statistics were used to summarise publication and congress abstract characteristics. Categorical variables were presented as absolute numbers and percentages, whereas continuous variables were expressed as means when appropriate. Temporal changes in the proportion of basic/translational versus clinical publications were assessed using logistic regression, with publication year included as a continuous variable. Differences in the proportion of Q1 publications according to study type, as well as differences in leadership between men and women leadership between clinical and basic/translational research, were evaluated using Pearson's chi-square tests. The distribution of oral versus poster presentations across ECCO study types was compared using Fisher's exact test because of small cell counts. A two-sided p-value <0.05 was considered statistically significant. Statistical analyses and data visualisation were performed using R version 4.4.1 (R Foundation for Statistical Computing, Vienna, Austria). Figures were generated with the ggplot2 package, and geographic maps were created using mapSpain.
ResultsLandscape of Spanish IBD research in specialized indexed journalsDuring 2020–2024, Spanish participation in clinical and basic/translational IBD research accounted for 1361 PubMed-indexed publications (mean 272.2 per year; Fig. 2A). Globally, 42,734 IBD publications were identified during the same period (mean 8546.8 per year; Fig. 2B), indicating that Spain contributed approximately 3% (n=1361/42,734) of worldwide scientific output.
Scientific output in IBD research between 2020 and 2024. (A) Number of publications with Spanish participation. (B) Global scientific production in inflammatory bowel disease. (C) Distribution and temporal evolution of publications according to study type. (D) Quartile distribution of journals publishing Spanish inflammatory bowel disease research. (E) Quartile distribution according to study type. (F) Regional distribution of publications by autonomous community. (G) Regional distribution of basic and translational research publications by autonomous community.
Basic/translational and clinical research represented distinct components of Spanish IBD scientific output and were analysed according to their impact and regional distribution. Basic/translational research accounted for 38.7% of the total output (n=527), whereas clinical research represented 61.3% (n=834). When analysing the temporal evolution of these publications by study type (Fig. 2C), the number of clinical research studies remained rather stable over the period analysed, whereas there has been a significant decrease in the number of basic/translational research articles published over the past five years (OR per year=0.85, 95% CI 0.78–0.92; p<0.001). Altogether, this data highlights the relevance of clinical research articles lead by Spanish researchers, and underscores an opposite publication trend compared to basic/translational research in recent years.
Journal ranking characteristics of these publications were analysed according to the journals in which they were published. Of the 1361 articles with Spanish authorship, the majority were published in high-impact journals: 72.6% (n=952) in Q1 journals and 15.1% (n=198) in Q2 journals, with smaller proportions in Q3 (10.6%; n=139) and in Q4 (1.8%; n=24) journals (Fig. 2D). This distribution indicates that almost 85% of Spanish output appears in Q1–Q2 journals. Importantly, within the Q1 category, nearly one-third of the publications (30.6%; n=291) were placed in first-decile (D1) journals. The average impact factor of these D1 journals was 15.2, reflecting publication in leading journals and venues in the field. Publications within this top quartile frequently incorporated advanced cellular and molecular methodologies. When separated by study type, both basic/translational and clinical research were predominantly published in Q1 journals. However, the proportion of Q1 publications was higher for basic/translational research compared to clinical research (78.6% vs 68.6%; χ2=15.241, p<0.001), indicating a greater concentration of basic/translational studies in the highest journal-ranking tier (Fig. 2E).
The geographical distribution of Spanish IBD research was also evaluated. As shown in Fig. 2F, Madrid and Catalonia showed the highest number of publications. Interestingly, when normalized by the population of each region, Madrid (3.4 articles/100K inhabitants) and Catalonia (2.6 articles/100K inhabitants) remain highly productive. However, Aragón (3.1 articles/100K inhabitants) and Cantabria (3.1 articles/100K inhabitants) also showed research publication rates similar to Madrid. Regarding basic/translational research, the number of publications followed a trend similar to that of the total Spanish research production (Fig. 2G). Still, when normalized per capita, basic/translational research demonstrates a more homogeneous distribution across all regions, with the exceptions of Castilla y León, Islas Baleares, Islas Canarias, La Rioja, Navarra, Castilla la Mancha, Ceuta and Melilla, which show lower publication rates (<0.3 articles/100K inhabitants).
Collaborative networks and international presenceThe structure and intensity of international collaborative networks involving Spanish researchers were analysed. The data obtained allowed us to analyse the main international collaborators in terms of published papers. Fig. 3A shows the ten countries with the highest number of articles co-authored by Spanish researchers in collaboration with a foreign principal investigator (PI). More than 80 articles (16.2%) with Spanish co-authors were led by researchers based in the USA, followed by over 50 articles in collaboration with PIs from the UK and Italy, each representing more than 10% of the total. A substantial number of articles with Spanish contributions were also published in collaboration with French, Belgian, German, and Canadian PIs, each accounting for 5–10% of the included articles. International collaborations were further analysed according to study type, exploring whether they primarily reinforced clinical research or also contributed to basic/translational advancement. As shown in Fig. 3B, clinical research represented the majority of internationally co-authored publications (62.8%), whereas basic/translational studies accounted for approximately 37%. Taken together, these findings illustrate the extent of international collaboration involving Spanish researchers, while also indicating that these networks presently reinforce a predominantly clinical research profile, with room to further bolster basic/translational collaboration.
International collaboration, leadership, and characteristics of Spanish inflammatory bowel disease research publications (2020–2024). (A) International collaborations involving Spanish researchers. (B) Distribution of internationally co-authored publications according to study type. (C) National and international leadership according to study type. (D) Gender distribution of national principal investigators. (E) Gender distribution of national principal investigators according to study type. (F) Original publications according to research category. (G) Distribution of research topics according to study type. (H) Experimental models used across study types. (I) Methodological approaches in translational and basic research. Abbreviations: PI, principal investigator; PBMCs, peripheral blood mononuclear cells; iPS, induced pluripotent stem cells; scRNA-seq, single-cell RNA sequencing.
Leadership roles in basic/translational and clinical research were analysed according to national and international contributions (Fig. 3C). Both types of studies involving Spanish researchers showed a higher percentage of national leadership (>60%). It is also noteworthy that approximately 35% of the studies – both basic/translational and clinical – were led by foreign PIs. Of note, in both categories men led most of the studies nationally representing similar percentages. In contrast, women investigators led a significantly higher percentage of basic/translational research articles compared to clinical research papers (χ2=13.449, p<0.001). Lastly, the basic/translational research articles led by study groups were low, representing only 9% of clinical research papers.
Among the studies supervised by national PIs, 57.9% were led by men and 34.6% by women, while the remaining 7.5% were comprised of mixed-gender Spanish study groups (Fig. 3D). The gender distribution of national PIs varied across different study categories. Whereas men were more frequently represented as leaders of clinical studies, women led basic/translational and clinical research studies in similar proportions (Fig. 3E).
Topical focus and research modelsSpanish publications between 2020 and 2024 were classified according to research topics across clinical, translational, and basic domains. From 1361 publications, only original articles (67.5%, n=919) were included in the analysis.
The proportion of original studies differed across research categories, being highest in basic research (77.7%, n=174), followed by clinical research (69.5%, n=577) and translational research (58.7%, n=168) (Fig. 3F). This indicates a higher relative contribution of original research in basic studies despite the predominance of clinical output.
Publications were classified into seven research topics: treatment, epidemiology, diagnosis, pathophysiology, comorbidities, nutrition, and microbiota (Fig. 3G). In clinical research (n=577), treatment predominated (55.3%, n=319), followed by epidemiology (18.2%, n=105) and diagnosis (14%, n=81). In translational research (n=168), pathophysiology (28%, n=47), treatment (26.8%, n=45), and diagnosis (23.2%, n=39) were similarly represented. In basic research (n=174), pathophysiology accounted for nearly half of publications (47.7%, n=83), followed by treatment (23.6%, n=41) and microbiota (17.8%, n=31). Other topics, including epidemiology, nutrition, and diagnosis, were less frequent (<10%), although nutrition-related studies (7.5%, n=13) are emerging as an area of growing interest.
Experimental models in original articles (n=919) were classified as patient-based, in vivo, or in vitro (Fig. 3H). Clinical research relied exclusively on patient-based studies (100%, n=577). In translational research, most studies included patients (96.4%, n=162), while in basic research, 41.4% (n=72) incorporated patient material, reflecting the emphasis on clinically derived samples. Basic research also included in vivo (45.4%, n=79) and in vitro models (13.2%, n=23).
Studies were classified as conventional, advanced, or ex vivo according to the methodological approach employed (Fig. 2I). Translational research predominantly used advanced techniques (55.4%), followed by conventional (28.6%) and ex vivo approaches (12.5%). Basic research showed a more heterogeneous profile, with advanced methods (19.5%), ex vivo models (17.8%), and limited conventional approaches (4%).
These findings highlight the widespread use of advanced methodologies and the increasing technical maturity of Spanish IBD research.
Spanish contributions to ECCO congressesSince 2019, Spanish researchers contributed with 638 abstracts to ECCO congresses, representing 8.5–12.4% of accepted communications annually (80–126 abstracts; Fig. 4A). Most abstracts were clinical (77.3%, n=493), followed by translational (12.1%, n=77) and basic research (10.7%, n=68) (Fig. 4B). Oral presentations accounted for 7.97% (n=51) of contributions (range 5.4–13.1%; Fig. 4C), with significantly higher representation in translational studies (18.2%, n=14/77) than in clinical (8.7%, n=43/493) and basic research (7.4%, n=5/68) (Fisher's exact test, p=0.040; Fig. 4D).
Characteristics of Spanish inflammatory bowel disease research in ECCO congresses and detailed analysis of original studies (2019–2024). (A) Annual number of abstracts and proportion of Spanish abstracts. (B) Distribution of abstracts according to study type. (C) Oral presentations by year. (D) Type of presentation according to study category. (E) ECCO topic categories represented in the abstracts. (F) Country of affiliation of the principal investigator. (G) Distribution of internationally co-authored abstracts according to study type. (H) Regional distribution of abstracts by autonomous community. (I) Regional distribution of basic and translational research abstracts by autonomous community. (J) Gender distribution of principal investigators according to investigator affiliation. (K) Distribution of study type according to gender and affiliation of the principal investigator. Abbreviation: ECCO, European Crohn's and Colitis Organisation.
Treatment-related research predominated, followed by epidemiology and diagnosis. Basic and translational studies mainly addressed pathophysiology, representing 42.3% and 73.8% of their outputs, respectively (Fig. 4E).
International collaboration was frequent, with approximately one third of abstracts (33.3%, n=213/638) led by investigators based outside Spain, most commonly from the USA (28.2%), the UK, and Belgium (both 9.7%) (Fig. 4F). These collaborations were predominantly clinical (91.3%), with limited translational (5.8%) and basic participation (2.9%) (Fig. 4G).
Within Spain, contributions were concentrated in Catalonia (n=132 abstracts) and Madrid (n=125), followed by Valencia (n=73) and Galicia (n=70). Adjusted for population, Galicia showed the highest productivity (2.6 abstracts/100,000 inhabitants), followed by Madrid and Cantabria (1.9) and Catalonia (1.7) (Fig. 4H). Basic and translational output was highest in Catalonia and Valencia, with Cantabria, Catalonia, and Valencia showing the greatest research intensity after adjustment (0.6–0.9 abstracts/100,000 inhabitants) (Fig. 4I).
Authorships led by men predominated overall (62.1%, n=396) compared with those led by women (37.9%, n=242), although the gap narrowed in basic research, where women represented half of national PIs. Men predominated in clinical and translational studies (Fig. 4J–K).
DiscussionSpain maintains substantial scientific activity in IBD research, with sustained publication output, international collaboration, and consistent participation in ECCO congresses. Spanish contributions to ECCO included a substantial proportion of basic and translational research, highlighting the diversity of research activity within the national IBD community.16
Despite relatively low national investment in research and development (1.49% of GDP vs 2.26% EU-27 average18), Spain demonstrates substantial scientific productivity in IBD research. One possible contributing factor is the presence of collaborative structures such as Centro de Investigación Biomédica en Red (CIBER)19 and GETECCU,20 which integrate basic and clinical research and strengthen translational capacity.
However, this efficiency coexists with structural limitations that may affect sustainability. Recruitment and retention of early-career researchers remain challenging due to fragmented funding schemes, contributing to talent loss. The lack of a professionalized laboratory manager track further shifts administrative tasks to researchers, reducing efficiency. Basic and translational research account for roughly one third of output, highlighting the need for stronger integration with clinical research. Basic and translational research activity is concentrated in Catalonia, Madrid, and Galicia, where advanced infrastructures are available, while other regions show limited capacity. Strengthening structured clinical–basic collaboration is therefore essential. Consistently, studies incorporating patient cohorts, experimental models, and advanced analytical tools were frequently represented among publications in higher-ranked journals.21
Finally, this review identifies persistent gender disparities in leadership. Although representation of women is higher in basic and translational research, inequalities remain in clinical research and conference participation, consistent with previous reports.22,23 Similar gaps exist across gastroenterology, with women underrepresented in leadership roles, high-impact journals, and clinical trials.24,25 However, recent data suggest gradual improvement, with Spain showing a high proportion of women principal investigators (47.99%).26 These findings are consistent with reports from other European countries showing persistent barriers for women in scientific leadership despite progressive improvements in recent years.
This study has several limitations. First, publication retrieval was based exclusively on PubMed and may not have captured all relevant contributions indexed in other bibliographic databases such as Scopus or Web of Science, nor non-indexed scientific outputs. In addition, congress activity was assessed exclusively through ECCO meetings and may not fully represent Spanish participation in other international gastroenterology and IBD congresses. Second, the classification of publications and abstracts involved a degree of manual assessment, which may introduce some subjectivity. Gender assignment was based primarily on author first names and publicly available information, which may have resulted in occasional misclassification, particularly in cases of ambiguous names. Third, regional productivity was normalized according to population size, an indirect measure that does not account for differences in research infrastructure, funding availability, or the number of active research groups across regions. Furthermore, the study was focused on the Spanish research landscape and was not designed to perform direct comparisons with other countries. Finally, the descriptive nature of the study does not allow causal inferences regarding the factors associated with scientific productivity or leadership patterns.
In conclusion, our descriptive characterisation of IBD research in Spain suggests a sustained scientific activity, supported by the use of advanced methodologies and international collaboration. However, regional differences in productivity, limited integration between research areas, and gender disparities in leadership remain relevant challenges.
Authors’ contributionsBM: conceptualization, visualization, supervision. ID, JC-A, ADP, CE-H, ML-S, JM, CS, LA, DO-M: methodology, investigation, data curation. ID, JC-A, ADP, CE-H, ML-S, JM, CS, LA, DO-M: writing – original draft. BM, ID, JC-A, ADP, CE-H, ML-S, JM, CS, LA, DO-M: writing – review & editing. DO-M: project administration, supervision. All authors have read and approved the final version of the manuscript.
Inclusion and diversity statementWe support inclusive, diverse, and equitable research.
Ethical considerationsThis is a review study; therefore, no ethical approval or informed consent was required.
FundingSpanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU).
Conflict of interestThe authors declared that there were no conflicts of interest associated with the manuscript.
The authors thank Azucena Salas, Fernando Gomollón, and Yamile Zabana for their valuable support and insightful comments, and Montse Baldan for her assistance in providing information related to the ECCO Congress. The authors also thank Joe Moore for editorial assistance. In addition, the authors acknowledge the support of the GETECCU leadership and administration for their institutional commitment and continued support for the development and promotion of GETECCU-BAS initiatives.
