Disease exacerbation is common in inflammatory bowel disease patients treated with immune checkpoint inhibitors for malignancy

Table 1 Baseline demographics and inflammatory bowel disease characteristics stratified by inflammatory bowel disease diagnosis

	Crohn's disease	Ulcerative colitis	Indeterminate IBD
	n = 4	n = 14	n = 1
Demographics
Age at first ICI use, yr, median, IQR	63, 4	69, 12.5	60, 0
Female sex, n (%)	2 (50.0)	2 (14.3)	0 (0)
White race, n (%)	3 (75.0)	11 (78.6)	1 (100)
Black race, n (%)	1 (25.0)	1 (7.1)	0 (0)
Asian race, n (%)	0 (0)	1 (7.1)	0 (0)
Other race, n (%)	0 (0)	1 (7.1)	0 (0)
Non-Hispanic ethnicity, n (%)	4 (100)	12 (85.7)	1 (100)
Hispanic/Latino ethnicity, n (%)	0 (0)	2 (14.3)	0 (0)
Never smoker, n (%)	2 (50.0)	5 (35.7)	0 (0)
Former smoker, n (%)	2 (50.0)	9 (64.3)	1 (100)
Body mass index, median, IQR	21.6, 1.7	25.5, 6.1	24.1, 0
IBD characteristics
Age at IBD onset, yr, median, IQR1	56, 0	39.5, 32.8	54, 0
IBD duration, yr, median, IQR1	7, 1	20, 29.25	6, 0
Disease location, n (%)	L1: 1 (25.0)	E1: 1 (7.1)	-
	L2: 1 (25.0)	E2: 4 (28.6)	-
	L3: 2 (50.0)	E3: 7 (50.0)	-
	-	Unknown: 2 (14.3)	-
Disease behavior, n (%)	B1: 2 (50.0)	-	-
	B2: 1 (25.0)	-	-
	B3: 0 (0)	-	-
	Unknown: 1 (25.0)	-	-
Perianal disease, n (%)	0 (0)	-	-
Extra-intestinal manifestations, n (%)	0 (0)	0 (0)	0 (0)

¹Unknown for 2 CD and 4 UC patients because date of IBD onset was not available.

Disease location and behavior were categorized using the Montreal classification: Location (L): L1, ileal disease; L2, colonic disease; L3, ileocolonic disease; Behavior (B): B1, inflammatory phenotype; B2, obstructive/stricturing phenotype; B3, penetrating/fistulizing phenotype; Extent (E): E1, proctitis; E2, left-sided colitis; E3, extensive/pan colitis. IQR: Interquartile range; IBD: Inflammatory bowel disease; ICI: Immune checkpoint inhibitor.