Inflammatory bowel disease in India - Past, present and future

Abstract

There is rising incidence and prevalence of inflammatory bowel disease (IBD) in India topping the Southeast Asian (SEA) countries. The common genes implicated in disease pathogenesis in the West are not causal in Indian patients and the role of “hygiene hypothesis” is unclear. There appears to be a North-South divide with more ulcerative colitis (UC) in north and Crohn’s disease (CD) in south India. IBD in second generation Indian migrants to the West takes the early onset and more severe form of the West whereas it retains the nature of its country of origin in migrants to SEA countries. The clinical presentation is much like other SEA countries (similar age and sex profile, low positive family history and effect of smoking, roughly similar disease location, use of aminosalicylates for CD, low use of biologics and similar surgical rates) with some differences (higher incidence of inflammatory CD, lower perianal disease, higher use of aminosalicylates and azathioprine and lower current use of corticosteroids). UC presents more with extensive disease not paralleled in severity clinically or histologically, follows benign course with easy medical control and low incidence of fulminant disease, cancer, complications, and surgery. UC related colorectal cancer develop in an unpredictable manner with respect to disease duration and site questioning the validity of strict screening protocol. About a third of CD patients get antituberculosis drugs and a significant number presents with small intestinal bleed which is predominantly afflicted by aggressive inflammation. Biomarkers have inadequate diagnostic sensitivity and specificity for both. Pediatric IBD tends to be more severe than adult. Population based studies are needed to address the lacunae in epidemiology and definition of etiological factors. Newer biomarkers and advanced diagnostic techniques (in the field of gastrointestinal endoscopy, molecular pathology and genetics) needs to be developed for proper disease definition and treatment.

Keywords: Inflammatory bowel disease; Ulcerative colitis; Crohn’s disease; India; Review

Core tip: There is growing interest in inflammatory bowel disease (IBD) in India due to its rising incidence. This review addresses the current state of knowledge on different aspects of Indian IBD patients like epidemiology, genetics, mechanisms, clinical presentations and treatment (compared to other south Asian countries) in the context of which future areas of research is highlighted. The disease is milder in India. Well-designed population based studies are needed. To address the obscure pathogenesis and uncertain disease course (behaviour, activity, treatment response, development of cancer and prognosis) studies on mechanisms, biomarkers, advanced endoscopic techniques need to be done to decrease the morbidity burden.