P653 Increasing prevalence of paediatric Inflammatory Bowel Disease in Japan: Direct comparison with adult disease using national registry data
T. Ishige*1, T. Tomomasa1, R. Hatori1, M. Tatsuki1, Y. Igarashi1, K. Arai2, H. Arakawa1
1Gunma University, Department of Pediatrics, Maebashi, Japan, 2National Center for Child Health and Development, Division of Gastroenterology, Tokyo, Japan
Background: An increased incidence and prevalence of paediatric inflammatory bowel disease (IBD) has been reported in Western countries; however, changes in the prevalence of paediatric IBD in Asian countries remain unclear. This study evaluated changes in the prevalence of IBD among Japanese adults and children between 2004 and 2011.
Methods: Age-standardized prevalence and male to female ratios among Japanese IBD patients were analysed using the Japanese national registry database of patients receiving public financial aid for intractable diseases. Data for adults (aged ≥ 20 years) were compared to those for children (aged 0-19 years).
In 2004, 24,112 patients with Crohn's disease (CD) and 82,576 with ulcerative colitis (UC) were registered. Among them, 1012 CD (4.2%) and 2679 UC (3.2%) patients were under 20 years of age. The age-standardized prevalences of CD and UC were 4.2/100,000 and 11.0/100,000 among children, respectively; the corresponding prevalences among adults were 22.7/100,000 and 78.4/100,000, respectively. In 2011, 1504 (4.1%) of the 36,225 CD and 3302 (2.4%) of the 136,845 UC patients were under 20 years of age. The age-standardized prevalences of paediatric CD and UC were 6.7/100,000 and 14.6/100,000, respectively; the corresponding adult prevalences were 33.5/100,000 and 128.9/100,000, respectively. The prevalence of paediatric CD increased by 60.0% between 2004 and 2011, and by 47.8% in the adult population (NS). During this period, the prevalence of UC increased by 64.4% among adults, and by 32.5% among children (P < 0.001). The male to female ratio among paediatric patients increased for both CD and UC (CD, 1.98 to 2.13; UC, 1.35 to 1.40).
Conclusion: The prevalence of Japanese children with IBD has increased rapidly in recent years, with a trend towards a CD-dominance of IBD in the paediatric population. Conversely, the increase is UC-dominant among adult patients. This discrepancy between paediatric and adult IBD trends may provide further insight.