Table 1.

Overall patient characteristics at baseline [N = 1898].

Baseline characteristic	Overall N = 1898	Surgery group N = 130 6.8%	No surgery group N = 1768 93.1%	Complication group N = 504 26.6%	No complication group N = 1394 73.5%
Demographics
Age, years [mean ± SD]	44.0 ± 14.6	42.7 ± 14.0	44.1 ± 14.6	42.1 ± 14.6	44.7 ± 14.5
Female	1097 [57.78%]	68 [52.3%]	1029 [58.2%]	311 [61.7%]	786 [56.4%]
Smoking status
Non-smoker	939 [49.5%]	58 [44.6%]	881 [49.9%]	241 [47.9%]	698 [50.1%]
Ex-smoker	550 [29.0%]	36 [27.7%]	514 [29.1%]	405 [29.1%]	145 [28.8%]
Current smoker	407 [21.44%]	36 [27.7%]	371 [21.0%]	290 [20.8%]	233 [11.7%]
Disease characteristics
Duration, months (mean [median])	148.8 [119]	144.8 [111.1]	149.1 [119.2]	147.0 [114.0]	149.5 120.9
HBI score [median; mean ± SD]	3; 4.1 ± 1.1	5; 6.0 ± 3.5	3; 4.0 ± 1.1	4; 5.0 ± 4.9	3; 3.8 ± 3.8
Steroid-free remission [HBI ≤ 4]	1,065 [56.1%]	51 [39.2%]	1014 [57.4%]	236 [46.8%]	829 [59.5%]
Extra-intestinal manifestations at baseline (n [%])	594 [31.3%]	55 [42.3%]	539 [30.5%]	185 [36.7%]	409 [29.3%]
Previous history of disease-related surgery	864 [45.5%]	56 [43.1%]	808 [45.7%]	244 [48.4%]	620 [44.5%]
Involved intestinal areas
Colon	417 [22.0%]	17 [13.1%]	400 [22.6%]	92 [18.3%]	325 [23.3%]
Small bowel	654 [34.5%]	52 [40.0%]	602 [34.1%]	169 [33.5%]	485 [34.8%]
Colon and small bowel	827 [43.6%]	61 [46.9%]	766 [43.3%]	243 [48.2%]	584 [41.9%]
Concurrent medications use
Aminosalicylates	539 [28.4%]	22 [16.9%]	517 [29.2%]	116 [23.0%]	423 [30.3%]
Corticosteroids	348 [18.3%]	31 [23.9%]	317 [17.9%]	113 [22.4%]	235 [16.9%]
Anti-metabolites	826 [43.5%]	48 [36.9%]	778 [44.0%]	204 [40.5%]	622 [44.6%]
TNF antagonists	622 [32.8%]	53 [40.8%]	569 [32.2%]	201 [39.9%]	421 [30.2%]

Figures may vary slightly from those published in Khanna et al. [2015], due to exclusion of 84 patients with at least one missing predictor variable.

SD, standard deviation; HBI, Harvey-Bradshaw Index; TNF, tumour necrosis factor.