Comprehensive Review of the Epidemiology, Pathogenesis, Diagnosis, and Treatment of Inflammatory Bowel Disease: Insights from the Past Two Years
Authors: Jian Wan1, Jiaming Zhou1, Zhuo Wang1, Dan Liu1, Hao Zhang1, Shengmao Xie2, Kaichun Wu1
Affiliations:
1State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi’an, Shaanxi 710032, China;
2Department of Gastroenterology, the 969th Hospital of the Joint Logistics Support Force of PLA, Huhehaote, Inner Mongolia 010051, China.
Abstract
Inflammatory bowel disease (IBD), encompassing ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic inflammatory condition of the gastrointestinal tract with an unknown etiology. The disease is multifactorial, involving genetic susceptibility, environmental factors, and dysbiosis of the gut microbiome. While the incidence of IBD has stabilized in Western countries, it is rapidly increasing in newly industrialized regions, particularly China. Advances in technology have enabled earlier diagnosis and real-time monitoring of disease activity through telemedicine tools, such as home-testing kits and wearable devices. The past two years have seen the introduction of novel therapeutic agents, including interleukin-23 inhibitors and small-molecule drugs. However, approximately one-third of patients remain non-responsive to initial treatments, and half lose response over time. Precision medicine, advanced combination therapies, and complementary approaches like stem cell transplantation and gut microbiome modulation offer promising avenues to overcome these challenges. This review highlights key advancements in the epidemiology, pathogenesis, diagnosis, and treatment of IBD over the past two years.
Keywords: Epidemiology, Pathogenesis, Diagnosis, Telemedicine, Treatment, Inflammatory bowel disease
Introduction
Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is a chronic, relapsing-remitting inflammatory condition of the gastrointestinal tract. Despite significant progress in understanding its etiology, the exact causes remain elusive. IBD is increasingly recognized as a global disease, with rising incidence in newly industrialized countries, particularly China. This review focuses on the latest advancements in the epidemiology, pathogenesis, diagnosis, and treatment of IBD over the past two years.
Epidemiology
The epidemiology of IBD has evolved through four stages: emergence, acceleration in incidence, compounding prevalence, and prevalence equilibrium. In Western countries, the incidence of IBD has stabilized, but prevalence continues to rise due to increased survival rates. For example, in Canada, the incidence is projected to remain stable at 30 per 100,000, while prevalence is expected to exceed 1.1% of the population by 2035. In contrast, newly industrialized countries, particularly in Asia and Latin America, are experiencing a sharp increase in incidence. China, for instance, has seen a national IBD incidence of 10.04 per 100,000 person-years, with higher rates in southern regions. This rise is attributed to rapid urbanization, westernization, and lifestyle changes.
Pathogenesis
The pathogenesis of IBD is multifactorial, involving genetic susceptibility, environmental triggers, and gut microbiota dysbiosis. Genome-wide association studies (GWAS) have identified over 320 genetic loci associated with IBD, with notable differences between East Asian and European populations. Environmental factors such as smoking, diet, and exposure to pesticides and microplastics exacerbate inflammation in genetically predisposed individuals. Dysbiosis of the gut microbiome, particularly reductions in short-chain fatty acid-producing bacteria, plays a critical role in disease initiation and progression. Dysregulated immune responses, including abnormal activation of innate and adaptive immunity, further contribute to chronic inflammation.
Diagnosis and Assessment
Early diagnosis and accurate assessment of disease activity are crucial for improving IBD outcomes. Significant changes in biomarkers, such as fecal calprotectin and serum cytokines, can be detected years before clinical diagnosis, offering opportunities for early intervention. Endoscopic healing remains the gold standard for assessing disease activity, but non-invasive techniques like intestinal ultrasound and fecal biomarkers are gaining traction. Telemedicine tools, including home-testing kits and wearable devices, enable real-time monitoring of disease activity and treatment response, reducing the need for frequent hospital visits.
Treatment
The past two years have seen the introduction of several novel therapeutic agents for IBD. Interleukin-23 inhibitors, such as mirikizumab and risankizumab, have shown promising results in clinical trials. Small-molecule drugs like etrasimod and upadacitinib offer oral alternatives to biologics. Despite these advancements, treatment response remains suboptimal for many patients. Advanced combination therapies, precision medicine, and complementary approaches like stem cell transplantation and gut microbiome modulation are being explored to overcome these challenges.
Future Directions
Future research should focus on identifying preclinical biomarkers, developing AI-driven predictive models, and evaluating early intensified treatment strategies. Non-invasive monitoring technologies and home-based testing tools will play a crucial role in personalized disease management. Head-to-head trials comparing the efficacy of different therapeutic agents and the integration of multi-omics data into precision medicine approaches hold promise for breaking the therapeutic ceiling in IBD.
Conclusion
Inflammatory bowel disease remains a complex and challenging condition, but significant progress has been made in understanding its epidemiology, pathogenesis, and treatment. The introduction of novel therapeutic agents and advancements in diagnostic and monitoring technologies offer hope for improved patient outcomes. However, further research is needed to address the limitations of current treatments and develop personalized, precision-based approaches to IBD management.
References
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- Kaplan GG, Windsor JW. The four epidemiological stages in the global evolution of inflammatory bowel disease. Nat Rev Gastroenterol Hepatol 2021;18:56-66. doi: 10.1038/s41575-020-00360-x
- Wan J, Shen J, Zhong J, et al. Natural course of ulcerative colitis in China: Differences from the West? United Eur Gastroenterol J 2024;12:1167-1178. doi: 10.1002/ueg2.12634
- Mao R, Chen M. Precision medicine in IBD: Genes, drugs, bugs and omics. Nat Rev Gastroenterol Hepatol 2022;19:81-82. doi: 10.1038/s41575-021-00555-w
DOI: 10.1097/CM9.0000000000003542
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