Nested case-control study on risk factors for opportunistic infections in patients with inflammatory bowel disease

Table 1 Opportunistic infections in inflammatory bowel disease patients evaluated between January 1, 2017 and December 31, 2018

Organism	Number of UC patients	Number of CD patients
Mycobacterium tuberculosis	1	0
Epstein-Barr virus	10	5
Cytomegalovirus	3	1
Hepatotropic virus	0	1
Clostridium difficile	11	13
Adenovirus	0	3
Syncytial virus	5	11
Coxsaccie virus	1	2
Herpes simplex virus	3	2
Herpes zoster	0	1
Mold	6	3
Candida albicans	2	0
Streptococcus	1	2

Three patients were co-infected with Epstein-Barr virus (EBV) and respiratory syncytial virus (S virus). Two patients were co-infected with EBV and mold. One patient was co-infected with EBV and Clostridium difficile (CDI). One patient was co-infected with EBV and cytomegalovirus (CMV). One patient was co-infected with EBV and herpes simplex virus (HSV). One patient was co-infected with EBV, S virus, and Coxsaccie virus (C virus). One patient was co-infected with mold and CDI. One patient was co-infected with adenovirus and S virus. One patient was co-infected with adenovirus and C virus. One patient was co-infected with CDI and C virus. One patient was co-infected with CDI and S virus. One patient was co-infected with CDI, mold, and Streptococcus. UC: Ulcerative colitis; CD: Crohn’s disease.

Table 2 Demographic and clinical features of inflammatory bowel disease patients with (cases) and without (controls) opportunistic infection

	Cases (n = 70)	Controls (n = 140)	P-value
Median age	45.67 ± 15.79	44.13 ± 14.21	0.45
Gender			0.11
Male	39	89
Female	31	51
Type of IBD			0.82
UC	33	66
Proctitis	4	24
Left-sided	7	15
Extensive	22	27
CD	37	74
Ileitis (L1)	9	23
Colitis (L2)	6	3
Ileocolitis (L3)	17	26
Upper gastrointestinal tract (L4)	1	4
L1 + L4	0	5
L2 + L4	0	2
L3 + L4	4	11
Duration of IBD (yr)	6.42 ± 6.01	5.12 ± 4.04	0.28
Duration of medication (yr)	2.73 ± 2.02	2.54 ± 2.11	0.71
Prior surgery	25	41	0.31
Smoking	2	13	0.11

L1; Ileitis; L2: Colitis; L3: Ileocolitis; L4: Upper gastrointestinal tract; IBD: Inflammatory bowel disease; UC: Ulcerative colitis; CD: Crohn’s disease.

Table 3 Risk factors for opportunistic infection in inflammatory bowel disease patients (univariate analysis)

	Cases (n = 70)	Controls (n = 140)	P-value	Odds ratio	95%CI
Disease activity
Remission	25	85	Reference
Mildly active	20	40	0.145	1.673	0.837-3.345
Moderate	14	13	0.004	3.604	1.505-8.626
Severe	11	2	<0.001	18.404	3.833-88.375
Treatment
5-ASA	20	83	Reference
Any IS	8	12	0.047	2.668	1.012-7.033
Any two IS	10	4	<0.001	10.375	2.948-36.508
Infliximab	13	24	0.109	1.992	0.857-4.632
5-ASA + any IS	11	9	0.002	5.072	1.853-13.887
Infliximab + any IS	9	7	0.003	5.336	1.773-16.058
FC > ULN	57	69	<0.001	4.431	2.265-8.667
CRP > ULN	26	18	<0.001	3.98	1.994-7.944
ESR > ULN	25	18	<0.001	3.744	1.87-7.494

5-ASA: 5-aminosalicylic acid; IS: Immunosuppressant (steroids, thiopurine, thalidomide, tacrolimus, or methotrexate); FC: Fecal calprotectin; CRP: C-reaction protein; ESR: Erythrocyte sedimentation rate; ULN: Upper limit of normal; CI: Confidence interval.