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. 2022 Sep 5;16(6):921–929. doi: 10.5009/gnl210488

Table 5.

Paris Classification and Disease Activity Indices

Classification Value
Crohn’s disease (n=227)
Age at diagnosis
A1a 18 (7.9)
A1b 175 (77.1)
A2 34 (15.0)
LGI involvement and location
L1 31 (13.7)
L2 33 (14.5)
L3 153 (67.4)
None 10 (4.4)
UGI involvement and location
L4a 69 (30.4)
L4ab 37 (16.3)
L4b 62 (27.3)
None 59 (26.0)
Luminal disease behavior
B1 168 (74.0)
B2 11 (4.8)
B3 46 (20.3)
B2B3 2 (0.9)
Perianal disease modifier
No 119 (52.4)
Yes 108 (47.6)
PCDAI 37.5 (30.0–47.5)
Ulcerative colitis (n=80)
Extent
E1 22 (27.5)
E2 9 (11.3)
E3 6 (7.5)
E4 43 (53.8)
PUCAI 40 (25–55)

Data are presented as number (%) or median (interquartile range). The classification in the table is as follows. A1a: age <10 yr, A1b: 10 to <17 yr, A2: age ≥17 yr. L1: distal 1/3 ileum±limited cecal disease, L2: colonic disease, L3: ileocolonic disease, L4a: upper disease proximal to ligament of Treitz, L4b: upper disease distal to the ligament of Treitz and proximal to the distal 1/3 ileum, L4ab: upper disease involvement in both L4a and L4b. B1: non-stricturing, nonpenetrating behavior, B2: stricturing behavior, B3: penetrating behavior, B2B3: both B2 and B3. E1: ulcerative proctitis, E2: left-sided UC (distal to splenic flexure), E3: extensive (hepatic flexure distally), E4: pancolitis (proximal to hepatic flexure).

UGI, upper gastrointestinal; PCDAI, pediatric Crohn’s disease activity index; PUCAI, pediatric ulcerative colitis activity index.