Table 1 Baseline characteristics

Population included

49

154

–

Observation time (months)

4646

6972

0.03*

Observed events (surgery)

6

23

Incidence rate (events\year)

0,02

0,04

Sex (male: n; %)

24 (49%)

97 (63%)

0.08*

Age at enrolment (median; range)

42 (20–78)

40 (15–85)

0.71†

Age at diagnosis (median; range)

36 (9–78)

34 (11–66)

0.43⁺

Disease duration (median; range)

72 (2–290)

36 (12–432)

< 0.01†

Early systemic steroid use

0.73*

‐ First year

‐ No use in the first year

27 (56%)

21 (44%)

91 (59%)

63 (41%)

Disease pattern

0.24*

‐ Penetrating and structuring disease

‐ Non penetrating nor structuring disease

21 (43%)

28 (57%)

81 (53%)

73 (47%)

Early onset

0.74*

‐ Before 17-year-old

‐ 17–40-year-old

‐ After 40-year-old

3 (6%)

30 (61%)

16 (33%)

15 (10%)

92 (60%)

47 (30%)

Ileal or jejunum involvement

0.39*

‐ Yes

‐ No

41 (84%)

8 (16%)

136 (88%)

18 (12%)

Active smokers

0.62*

‐ Yes

‐ No

17 (39%)

27 (61%)

66 (43%)

88 (57%)