Table 3.

Effect of appendicectomy on ulcerative colitis characteristics (n=307)

		Appendicectomy
Phenotype	n	Yes (n=21)	No (n=286)	OR (95%CI)	p Value
Mean (SEM) age at diagnosis (y)		37.8 (2.8)	31.3 (1.0)		0.08
Colectomy*
No	241	20 (100%)	221 (78.6%)
Yes	60	0 (0%)	60 (21.4%)		0.02
Immunosuppression
No	235	20 (95.2%)	215 (75.2%)	1.00 (referent)
Yes	72	1 (4.8%)	71 (24.8%)	0.15 (0.02–1.15)	0.04
Colectomy or immunosuppression†
No	195	20 (95.2%)	175 (62.3%)	1.00 (referent)
Yes	107	1 (4.8%)	106 (37.7%)	0.09 (0.01–0.66)	0.003
Distribution
L&P	173	8 (38.1%)	165 (57.9%)	1.00 (referent)
S&T	133	13 (61.9%)	120 (42.1%)	2.23 (0.9–5.56)	0.08
Duration between appendicectomy and UC (y)
S&T (mean (SEM))	13	15.5 (3.4)	—
L&P (mean (SEM))	8	10.3 (2.7)	—
Overall (mean (SEM))	21	13.5 (2.4)	—		0.30

S, subtotal colitis; T, total colitis; L, colitis distal to splenic flexure; P, ulcerative proctitis.

*Six patients excluded with colectomy for high grade dysplasia or colorectal carcinoma.

†Five patients excluded with colectomy for high grade dysplasia or colorectal carcinoma.