Disease phenotypic and outcome of very-early onset inflammatory bowel disease (VEO-IBD) in Asian Children: an understudied population

Way Seah Lee ^1,2* Kee Seang Chew ¹ James Guoxian Huang ³ Pornthep Tanpowpong ⁴ Karen SC Mercado ⁵ Almida Reodica ⁶ Veena Logarajah ⁷ Wathsala Hathagoda ⁸ Shaman Rajindrajith ⁸ Yoko Kin-Yoke Wong ⁹ Suporn Treepongkaruna ¹⁰ Marion Margaret Aw ³

• ¹ Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
• ² Tunku Abdul Rahman University, Kampar, Perak, Malaysia
• ³ National University of Singapore, Singapore, Singapore
• ⁴ Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Ratchathewi, Bangkok, Thailand
• ⁵ Makati Medical Center, Phillipines, Philippines
• ⁶ College of Medicine, University of the Philippines Manila, Manila, Philippines
• ⁷ KK Women's and Children's Hospital, Singapore, Singapore
• ⁸ Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
• ⁹ Singapore Clinical Research Institute, Biopolis Way, Singapore
• ¹⁰ Ramathibodi Hospital, Mahidol University, Bangkok, Thailand

Background: There is a paucity of knowledge on disease phenotype and outcome of very early-onset (VEO) inflammatory bowel disease (VEO-IBD) from recently developed and developing countries, including from Southeast Asia. We studied disease phenotype, clinical characteristics, management and outcome of VEO-IBD in South and Southeast Asian children.We extracted data from a multicentre Asian pediatric (onset < 18 years) IBD registry. VEO-and later-onset pediatric (LO-p) IBD were defined as onset of disease < 6 years and  6 years, respectively. We excluded monogenic IBD. Results: Of 440 children with IBD cases; 112 (25.5%) were VEO-IBD; Crohn's disease (CD) 36 (32.1%); ulcerative colitis (UC) 68 (60.7%), and IBD-unspecified 7 (7.1%). UC was more common in VEO-IBD while CD more common in LO-pIBD (CD=68.9% vs. UC=25.9%; p<0.001). Disease location/extent of disease and disease severity were similar in both age groups for both CD and UC. For CD, inflammatory disease behavior was equally common in both age group (77.8% in VEO-IBD vs. 76.6% of LO-pIBD), majority had isolated colonic disease (27.8% VEO-IBD vs. 36.3% LO-pIBD), while stricturing and penetrating diseases were not observed in VEO-CD, but noted in 4.9% and 8.4% of LO-pCD, respectively. Among UC cases, pancolitis was observed in 60.3% of VEO-IBD vs 65.9% of LO-pIBD. Most UC never had severe disease regardless of age group. Five years after diagnosis, VEO-IBD were more likely to have corticosteroids, immunomodulators or biologics than LO-pIBD. Despite this, inactive/mild disease activity was the predominant outcome at 5 year follow up for both VEO-CD (98.2%) and VEO-UC (96.1%). Bowel surgery rate was 2.4% and 1.7% for VEO-and LO-IBD at 5 years, respectively. Conclusions: Despite differences in disease phenotype at diagnosis, disease behaviour, location/extent and disease severity were similar between VEO-and LO-IBD, with a comparable overall clinical remission rates between both age groups at 5 years after diagnosis.