Study of disease phenotype and its association with prognosis of paediatric inflammatory bowel disease in China.

Background: To investigate the unique features of inflammatory bowel disease (IBD) in children, we wanted to identify whether there might be a strong correlation between the disease phenotype and its prognosis at various ages in paediatric patients.

Methods: We collected data from patients diagnosed with IBD (ulcerative colitis (UC) or Crohn's disease (CD)) from 2002 to 2016. The diagnosis was made according to the Porto criteria and Paris Classification. Patient characteristics, clinical manifestations and treatments were collected. Risk factors for surgery, mortality and relapse were analysed by Cox proportional hazard models.

Results: Of the 143 patients, 113 had CD, and 30 had UC; there were 89 males and 54 females with a median age of 9 years (y). Thirteen patients in the 0-2 y group were identified as having mutations in IL-10 receptor A, and this mutation was significantly more common in this age group than in 3-9 and 10-16 y patients. The risk factor for surgery was the B3 phenotype; risk factors for death were age 0-2 y and B3 phenotype; 0-2 y, B3 phenotype and steroid dependency were risk factors for early relapse.

Conclusions: Clinical manifestations of the onset of IBD in infants and toddlers were extensive and aggressive and were closely associated with early relapse and death. It is of particular interest that some of these patients developed IBD due to monogenic disorders; thus, introduction of genetic testing is essential for these patients.