How to predict clinical relapse in inflammatory bowel disease patients

Table 1 Clinical and environmental predictors of relapse in inflammatory bowel diseases patients

	CD	UC
Clinical factors
Age	Young age at diagnosis[6-8,10]	Young age at diagnosis[11,14,15]
	→Disabling chronic disease
		→Rate of relapse
Sex		Female[11,14]
		→Rate of relapse
Disease location	Perianal disease[7,9]	Extensive colitis[8,14,16]
	→Poor outcome	→risk of colectomy, CRC, mortality
	Terminal ileal location[8,9]
	→Predictor of stricturing/penetrating disease; risk of surgical resection
	Proximal small bowel/upper gastro-intestinal tract[10,11]
	→risk of relapse; risk of surgical resection
	Colonic disease[6]
	→risk of develop perianal disease
No. prior relapses	Short period of remission before relapse[5,6]	Greater number of prior relapse
	→poor prognosis	→shorter time to relapse
EIM	NS[12]	NS[12]
Environmental factors
Smoke	Disease severity[19,20]	↓ disease severity[21]
Appendectomy	Risk of surgical resection[24]	↓ risk of colectomy[22,26]
Drugs
NSAIDs/ COX-2 selective	Contrasting evidences[28]	Contrasting evidences[28]
OCPs	Risk of relapse[20]	NS[15]
HRT	↓ disease severity[29]	↓ disease severity[29]
Antibiotics	↓ risk of relapse[30]	NS[30]
Stress	Risk of relapse[32]	Risk of relapse[31]

CD: Crohn’s disease; UC: Ulcerative colitis; CRC: Colon-rectal cancer; EIM: Extraintestinal manifestation; NS: No significant; NSAIDs: Non-steroidal anti inflammatory drugs; COX-2: Cyclooxygenase-2; OPCs: Oral contraceptive pills; HRT: Hormone replacement therapy.