MICI: classification et nosologie le point de vue du clinicien Edouard Louis Service de Gastroentérologie, CHU Liège GIGAresearch, Université de Liège

Disease phenotypes in IBD why to bother ? CD1 CD2 CDx UC1 UC2 UCx CD IBD UC IC Different pathogenesis ? Different natural history ? Different response to treatment ?

To answer these questions, classifications must be tested to be validated Rome, 1991 Vienne, 1998 Montreal, 2005

CD: Vienne  Montreal Vienne Montreal Age at diagnosis Location L1 Ileal L2 Colonic L3 Ileocolonic L4 upper GI Behaviour B1 non-stricturing non-fistulizing B2 stricturing B3 fistulizing Montreal Age at diagnosis A1 <16 A2 16-40 A3 >40 Location L1 Ileal L2 Colonic + L4 upper GI L3 Ileocolonic L4 upper GI Behaviour (disease duration) B1 non-stricturing non-fistulizing B2 stricturing B3 intraabdominal penetrating + P perianal disease

Age at diagnosis <16 yrs: pediatric CD 16-40 yrs: classical CD Increasing incidence More upper GI CD More extensive CD 16-40 yrs: classical CD >40 yrs: CD in the elederly More colonic disease Differential diagnosis with ischemia

CD: Vienne  Montreal Vienne Montreal Age at diagnosis Location L1 Ileal L2 Colonic L3 Ileocolonic L4 upper GI Behaviour B1 non-stricturing non-fistulizing B2 stricturing B3 fistulizing Montreal Age at diagnosis A1 <16 A2 16-40 A3 >40 Location L1 Ileal L2 Colonic + L4 upper GI L3 Ileocolonic L4 upper GI Behaviour (disease duration) B1 non-stricturing non-fistulizing B2 stricturing B3 intraabdominal penetrating + P perianal disease

Upper GI CD: L4 Location proximal to the terminal ileum Specific problems and particular natural history Rarely isolated Prevalence depends on the techniques used for the diagnosis

Prevalence of small bowel CD with VCE Results of a meta-analysis Triester et al. Am J Gastroenterol 2006;101:954 Incremental Yield of VCE (%) SBFT N=9 P<0.001 ileoscop N=4 P=0.02 Enterosc N=2 P<0.001 MRI N=1 P=0.16 CT entero N=3 P=0.001

CD: Vienne  Montreal Vienne Montreal Age at diagnosis Location L1 Ileal L2 Colonic L3 Ileocolonic L4 upper GI Behaviour B1 non-stricturing non-fistulizing B2 stricturing B3 fistulizing Montreal Age at diagnosis A1 <16 A2 16-40 A3 >40 Location L1 Ileal L2 Colonic + L4 upper GI L3 Ileocolonic L4 upper GI Behaviour (disease duration) B1 non-stricturing non-fistulizing B2 stricturing B3 intraabdominal penetrating + P perianal disease

Penetrating CD: heterogeneous entity Association between perianal CD and internal fistulizing CD according to disease location Database records of 5491 CD pts from 6 centers No consistency for association in 1686 ileal CD (RR=0.8-2.2) Significant association in 1655 colonic CD P<0.0001 RR of association between Perianal and internal fistulizing Disease in colonic CD Sachar et al. Am J Gastroenterol 2005; 100: 1547

Development of stricturing and fistulizing CD over the course of the disease % Patients at risk. N= 297 259 218 187 125 74 47 32 Time (years) Louis et al. Gut 2001

Cumulative Probability (%) Development of stricturing and fistulizing CD over the course of the disease 100 90 80 70 Penetrating 60 Cumulative Probability (%) 50 40 30 Stricturing 20 Inflammatory 10 12 24 36 48 60 72 84 96 108 120 132 144 156 168 180 192 204 216 228 240 Months Patients at risk: N = 2002 552 229 95 37 Cosnes J et al. Inflamm Bowel Dis. 2002;8:244

A classification for Ulcerative colitis By extent E1: proctitis E2: left-sided colitis E3: extensive colitis Particular cases: periappendiceal infllammation, PSC-associated colitis By severity S0: inactive S1: mild S2: moderate S3: severe

Indeterminate colitis Diagnosis based on surgical specimen Overlapping features of both CD and UC Indeterminate colitis Diagnosis based on endoscopy with biopsies Chronic IBD, only colon involvement,non conclusive endoscopy, no infection, no microscopic feature specific for UC or CD Chronic IBD type unclassified

Drawbacks of current classification Definition of a phenotype depends on the techniques used to explore the patient: X-Ray, medical imaging, endoscopy, histology, biology. Instability over time of behaviour of CD, severity of UC and location of CD and UC Overlap between phenotypes: almost all fistulizing CD are associated with downstream strictures

Significant inflammation in macroscopically normal mucosa in CD Reimund et al. Gut 1996;39:684.

How to define a stricturing CD In Vienna classification: associated with symptoms or proximal dilatation Persistent stricture Inflammatory vs fibrotic stricture

Subobstructive CD 8 w. after Ifx

Drawbacks of current classification Definition of a phenotype depends on the techniques used to explore the patient: X-Ray, medical imaging, endoscopy, histology, biology. Instability over time of behaviour of CD, severity of UC and location of CD and UC Overlap between phenotypes: almost all fistulizing CD are associated with downstream strictures

Development of stricturing and fistulizing CD over the course of the disease % Patients at risk. N= 297 259 218 187 125 74 47 32 Time (years) Louis et al. Gut 2001

Behaviour of CD is a dynamic multifactorial polygenic character There is not really a time-limit after which a phenotype remains stable Genetic and environmental factors may influence the speed at which a phenotype develops Influence of genetic or environmental factors must be studied through multivariate analysis

Speed of development of stricturing CD stricture time

Drawbacks of current classification Definition of a phenotype depends on the techniques used to explore the patient: X-Ray, medical imaging, endoscopy, histology, biology. Instability over time of behaviour of CD, severity of UC and location of CD and UC Overlap between phenotypes: almost all fistulizing CD are associated with downstream strictures

Origin of non perianal fistulas in Crohn’s disease 60 specimens with fistulas, including 44 in first excisions 62% located at proximal end of a stricture 31% within a stricture 7% not associated with a stricture Kelly et al. J Clin Gastroenterol 1989;11: 193

Fistulizing CD: a mechanical theory Intraluminal hyperpressure

Are different phenotypes driven by different pathophysiology ? This would imply that a stable general phenotype exists for each patient

Influence of smoking of the phenotype of CD Brant et al. Inflamm Bowel Dis 2003 Picco et al. Am J Gastro 2003

Impact of disease phenotype on natural history That is mainly the phenotype at diagnosis which is important

Crohn’s disease location is the main factor influencing the development of complications CD behaviour 5 years after diagnosis Louis et al. Gut 2003

Subtype of penetrating CD after 5 years according to location of disease at diagnosis Intrabdominal penetrating disease was mainly associated with ileal location and perianal with colonic location (p<0.0001) Louis et al. Gut 2003

Perianal Crohn’s disease Cumulative frequency of 12% at 1 year, 15% at 5 ys, 26% at 20 ys Schwartz et al. Gastroenterology 2002; 122:875 Occurs in 12% of ileal CD, 41% of colonic CD, 92% in case of rectal involvement Hellers et al. Gut 1980; 21: 525

Recurrence rate in newly diagnosed CD The only factor independently associated with all recurrences was L4 location (P<0.01) Wolters et al. Gut 2006; 55: 1124.

Beaugerie et al. Gastroenterology 2006; 130: 650. Predictors of disabling CD Proportion of patients and predictive positive value of having a disabling CD in the 5-yr period after diagnosis. Score is based on the number of predictive factors at diagnosis: age<40, steroid treatment, perianal lesions. Beaugerie et al. Gastroenterology 2006; 130: 650.

Mortality over 10 years in newly diagnosed CD Increasing age was the only independent risk factor for both total and CD related mortality causes Wolters et al. Gut 2006; 55: 447.

Colectomy in UC after 5 years % Langholz et al. Gastroenterology 1992;103:1444

Colorectal cancer in UC after 30 years % Devroede et al. N Engl J Med 1971;285:17

Standard mortality ratio in UC SMR Ekbom et al. Gastroenterology 1992;103:954

Impact of disease phenotype on response to treatments That is mainly the phenotype at the time you treat the patient which is important

Budesonide and CD location 5ASA and UC extent 5ASA suppositories for proctitis 5ASA enemas for left colitis 5ASA tablets for extensive colitis Seksik et al. Gastroenterol Clin Biol 2004;28:964 Beaugerie et al. Gastroenterol Clin Biol 2004;28:974 Budesonide and CD location

Symptomatic luminal stricture underlies infliximab non-response in CD 95 patients treated with infliximab and evaluated after 6 months 45/95 did not respond or lost response and were explored 30/45 had underlying stricture or obstruction (28 small bowel and 2 colon) Prajapati et al. Gastroenterology 2002; 122: A777

Week 26 Response to Certolizumab pegol in precise 2 by Duration of Crohn’s Disease

Steroids may favour abdominal or pelvic abscesses Retrospective case-control study of 432 CD patients 29 patients with abscess and 57 with perforating disease without abscess Adjusted OR for systemic steroid for abscess development: 18.84 (2.32-152.73) 12 patients with initial non-perforating phenotype developping abscess over follow up vs 24 persisting non-perforating phenotype OR for systemic steroid for abscess development: 9.31 (1.03-83.91) Agrawal et al. Clin Gastroenterol Hepatol 2005; 3: 1215.

Conclusions Defining relevant phenotypes is a difficult task Phenotype definitions must be tested and validated with specific aims Different phenotypes of CD or UC have at least partly different pathophysiology Different phenotypes of CD and UC have different natural history Different phenotypes of CD and UC have different response to treatment

Research agenda Difference of composition of the fecal stream at different level of the colon in UC Characteristics of the inflammatory reaction at different GI levels in CD Difference in the characteristics of the lesions in early vs old CD and UC When studying biology of stricturing or fistulizing CD Take time into account Study the stricturing pattern by comparing B2+B3 to B1 and then fistulizing pattern by comparing B2 to B3