Table 2.

Incidence rates and hazard ratios (HRs) of inflammatory bowel disease (IBD), before and after propensity-score decile stratification

Outcome/CISD	CISD				Non-CISD				CISD vs. non-CISD
	Total patients	Person-years	Events	Incidence ratea	Total patients	Person-years	Events	Incidence ratea	Unadjusted HR (95% CI)	Adjusted HR (95% CI)b
IBD
Psoriasis	83 049	211 899	404	1·91	2 376 120	6 753 361	9761	1·45	1·37 (1·24–1·51)	1·06 (0·96–1·18)
Atopic dermatitis	123 614	425 768	691	1·62	2 376 120	6 753 361	9761	1·45	1·13 (1·05–1·22)	1·03 (0·95–1·11)
Alopecia areata	18 135	45 426	70	1·54	2 376 120	6 753 361	9761	1·45	1·06 (0·84–1·35)	1·18 (0·93–1·50)
Vitiligo	9003	23 204	39	1·68	2 376 120	6 753 361	9761	1·45	1·17 (0·86–1·60)	1·25 (0·91–1·71)
HS	6806	13 711	42	3·06	2 376 120	6 753 361	9761	1·45	3·00 (2·33–3·87)	2·21 (1·63–3·00)
Composite CISD	242 010c	723 174	1 251	1·73	2 376 120	6 753 361	9761	1·45	1·20 (1·13–1·27)	1·05 (0·98–1·12)
Ulcerative colitis
Psoriasis	83 049	212 221	287	1·35	2 376 120	6 760 059	7178	1·06	1·31 (1·17–1·47)	1·01 (0·89–1·14)
Atopic dermatitis	123 614	426 456	479	1·12	2 376 120	6 760 059	7178	1·06	1·06 (0·96–1·16)	1·02 (0·92–1·12)
Alopecia areata	18 135	45 483	50	1·1	2 376 120	6 760 059	7178	1·06	1·03 (0·78–1·37)	1·18 (0·89–1·56)
Vitiligo	9003	23 224	26	1·12	2 376 120	6 760 059	7178	1·06	1·05 (0·72–1·55)	1·14 (0·77–1·68)
HS	6806	13 735	31	2·26	2 376 120	6 760 059	7178	1·06	3·07 (2·29–4·12)	2·30 (1·61–3·28)
Composite CISD	242 010c	724 286	877	1·21	2 376 120	6 760 059	7178	1·06	1·15 (1·07–1·23)	1·03 (0·95–1·11)
Crohn disease
Psoriasis	83 049	212 497	143	0·67	2 376 120	6 769 184	3185	0·47	1·42 (1·20–1·68)	1·23 (1·03–1·46)
Atopic dermatitis	123 614	426 966	266	0·62	2 376 120	6 769 184	3185	0·47	1·34 (1·18–1·52)	1·08 (0·94–1·23)
Alopecia areata	18 135	45 543	26	0·57	2 376 120	6 769 184	3185	0·47	1·23 (0·84–1·80)	1·26 (0·86–1·86)
Vitiligo	9003	23 253	15	0·65	2 376 120	6 769 184	3185	0·47	1·44 (0·88–2·35)	1·45 (0·87–2·41)
HS	6806	13 757	16	1·16	2 376 120	6 769 184	3185	0·47	4·13 (2·83–6·03)	2·70 (1·69–4·32)
Composite CISD	242 010c	725 188	468	0·65	2 376 120	6 769 184	3185	0·47	1·38 (1·25–1·52)	1·12 (1·01–1·24)

CI, confidence interval; CISD, chronic inflammatory skin disease; HS, hidradenitis suppurativa.

^aPer 1000 person-years.

^bAdjusted by deciles of propensity score. All patient characteristics were included in the propensity-score model as independent variables.

^cPatients with psoriatic arthritis, defined as a diagnosis of psoriatic arthritis by a dermatologist and by a rheumatologist, were included in this composite but not analysed as an individual group as it was too small (< 1500).