Table 1.

Definition of high-risk patients based on ECCO/ESPGHAN consensus guidelines

Defining high-risk Crohn’s disease patients
ECCO/ESPGHAN consensus guidelines	Modified study criteria
Severe perianal disease	Complex perianal fistulising disease phenotype
Extensive (pan-enteric) disease; deep colonic ulcers on endoscopy	Panenteric disease phenotype (defined as L3 with L4b as per Paris classification25 or L3 with deep ulcers in the duodenum, stomach or oesophagus not related to non-steroidal anti-inflammatory medications or Helicobacter pylori)
	Overall cumulative disease extent of >/=60 cm
Stricturing and penetrating disease at onset	B2, B3 or B2B3 disease behaviour20
Marked growth retardation ≥2.5 height Z scores	Severe growth impairment (height z-score ≤2 or crossing ≥2 centiles) likely related to Crohn’s disease
Persistent severe disease despite adequate induction therapy	Hypoalbuminaemia (<30 g/L), elevated CRP (at least two times upper limit of normal range), or wPCDAI >12.5 despite at least 3 weeks of optimised induction therapy with steroids or EEN
Severe osteoporosis	Not included

CRP, C reactive protein; ECCO, European Crohn’s and Colitis Organisation; EEN, exclusive enteral nutrition; ESPGHAN, European Society for Paediatric Gastroenterology, Hepatology and Nutrition; wPCDAI, weighted Paediatric Crohn’s Disease Activity Index.