Table 5. Predictive clinical factors associated with the risk of perianal fistula in Korean patients with Crohn’s disease.

		Univariate analysis a		Multivariate analysis b
		5-year cumulative rate (%)	P value	HR	95% CI	P value
Age at diagnosis (%)			< 0.001
	< 40 years	39.1		3.15	2.05–4.86	< 0.001
	≥ 40 years	14.5		1 (Ref)
Gender			0.152
	Male	37.0		1.12	0.89–1.41	0.339
	Female	31.3		1 (Ref)
Family history of IBD (%)			0.136
	Yes	47.8		1.46	0.82–2.61	0.198
	No	35.1		1 (Ref)
Disease location at diagnosis (%) c			0.557
	Any ileal involvement	35.8		1.03	0.80–1.34	0.808
	No involvement of ileum	33.9		1 (Ref)
Concomitant UGI disease (L4)			0.359
	Yes	40.1		1.12	0.80–1.56	0.523
	No	35.0		1 (Ref)
Interval of diagnostic delay (%)			0.005
	< 3 months	29.9		1 (Ref)
	3–6 months	40.4		1.42	1.06–1.90	0.020
	6–18 months	40.7		1.42	1.09–1.85	0.009
	≥ 18 months	39.0		1.38	1.06–1.80	0.016

HR, hazard ratio; CI, confidence interval; IBD, inflammatory bowel disease; UGI, upper gastrointestinal.

^acalculated by a Kaplan-Meier survival model.

^banalyzed by a multivariate Cox proportional hazards regression model.

^cDisease location and behavior were determined according to the Montreal classification.