Table 4. Determinants of cumulative healthcare expenditure in patients with Crohn's disease based on the multivariate linear regression analysis.

Independent variables	Coefficient	(95% CI)	P value
Age (y)	-0.007	-0.013 - -0.001	0.029
Age at diagnosis (y)	0.005	-0.001 – 0.012	0.127
CRS prior to study	0.058	-0.111 – 0.227	0.499
LI2	0.01	0.004 – 0.0158	0.001
DLI	0.014	0.006 – 0.022	0.001
ESR elevation (/5y)	0.011	-0.037 – 0.599	0.645
CRP elevation (/5y)	0.023	-0.033 – 0.080	0.412
5y SIBDQ	-0.007	-0.014 - -0.001	0.024
5y HBI	0.01	-0.007 – 0.027	0.242
Phone calls to IBD clinic	0.001	-0.001 – 0.004	0.175
Psychiatric co-morbidities	0.068	-0.072 – 0.209	0.335

y: years; CRS: Crohn's disease related surgery (both outpatient and inpatient); LI2: Lémann index 2; DLI: Delta Lémann Index; CRP: C-reactive protein; SIBDQ: Short inflammatory bowel disease questionnaire; HBI: Harvey Bradhsaw Index; IBD: Inflammatory bowel disease