Table 4. Age- and sex-standardized prevalence ratios and 95% confidence intervals of the extraintestinal manifestations using a random sample of the entire Korean population as the reference population.

Extraintestinal manifestations	Crohn disease			Ulcerative colitis
	Observed events	Expected events	Standardized prevalence ratios (95% CI)	Observed events	Expected events	Standardized prevalence ratios (95% CI)
Ophthalmologic EIMs
Scleritis	6	4.7	1.28 (0.26–2.30)	29	12.9	2.24 (1.43–3.06)
Episcleritis	55	42.2	1.30 (0.96–1.65)	139	105.5	1.32 (1.10–1.54)
Iridocyclitis	107	55.6	1.92 (1.56–2.29)	339	151.7	2.23 (2.00–2.47)
Hepatopancreaticobiliary EIMs
Cholelithiasis	257	63.4	4.06 (3.56–4.55)	387	233.7	1.66 (1.49–1.82)
Sclerosing cholangitis	33	4.4	7.46 (4.92–10.01)	96	18.9	5.09 (4.07–6.10)
Acute pancreatitis	439	88.9	4.94 (4.47–5.40)	600	242	2.48 (2.28–2.68)
Dermatologic EIMs
Aphthous stomatitis	508	412.4	1.23 (1.12–1.34)	1,088	1,027.7	1.06 (1.00–1.12)
Psoriasis	123	94.5	1.30 (1.07–1.53)	359	232.2	1.55 (1.39–1.71)
Erythema nodosum	32	3.2	9.91 (6.47–13.34)	34	8.4	4.06 (2.69–5.42)
Pyoderma gangrenosum	8	1.8	4.43 (1.36–7.50)	21	4.8	4.36 (2.50–6.23)
Sweet syndrome	3	0.1	20.60 (0.00–43.91)	4	0.5	8.06 (0.16–15.96)
Musculoskeletal EIMs
Rheumatoid arthritis	496	217.3	2.28 (2.08–2.48)	1,180	728.8	1.62 (1.53–1.71)
Psoriatic arthritis	69	4.7	14.59 (11.14–18.03)	125	16.3	7.68 (6.34–9.03)
Ankylosing spondylitis	161	30.5	5.28 (4.46–6.10)	285	65.4	4.36 (3.85–4.87)
Sacroiliitis	16	4.7	3.37 (1.72–5.02)	29	14.7	1.98 (1.26–2.70)
Osteoporosis	882	330	2.67 (2.50–2.85)	2,445	1,590.2	1.54 (1.48–1.60)
Osteomalacia	6	4.8	1.26 (0.25–2.26)	20	18.4	1.09 (0.61–1.56)

CI, confidence interval; EIMs, extraintestinal manifestations.