Epstein-Barr virus infection is an independent risk factor for surgery in patients with moderate-to-severe ulcerative colitis

Table 3 Stratified analysis

	Conditional independence tests (χ2, P value)	OR parity test (P value)	Estimated combined OR (95%CI)
Age (≤ 51, > 51), year	26.588, P = 0.000	0.208	10.850 (3.726-31.594)
Fever	19.673, P = 0.000	0.635	9.254 (2.998-28.569)
CMV positivity	21.170, P = 0.000	0.712	10.669 (3.361-33.867)
Fungal infection	30.291, P = 0.000	0.437	14.969 (4.875-45.962)
Hemoglobin (≤ 113, >113) g/L	22.047, P = 0.000	0.708	12.459 (3.726-41.661)
CRP (≤ 11.74, > 11.74) mg/L	16.495, P = 0.000	0.339	10.979 (3.071-39.245)
ESR (≤ 27, > 27) mm/hour	28.514, P = 0.000	0.369	12.056 (4.070-35.715)
Albumin (≤ 35.2, > 35.2) g/L	20.065, P = 0.000	0.598	9.897 (3.119-31.409)
Prealbumin (≤ 163, >163) g/L	28.164, P = 0.000	0.127	10.992 (3.822-31.612)
Treatment with ≥ 3 types of immunosuppressive drugs before admission	42.469, P = 0.000	0.825	25.583 (7.836-83.531)
Antibiotic therapy with third-generation cephalosporins or more advanced antibiotics during admission	23.298, P = 0.000	0.087	12.659 (4.035-39.719)

CMV: Cytomegalovirus; OR: Odds ratio; CRP: C-reactive protein; ESR: Erythrocyte sedimentation rate.