Table 1.
Baseline characteristics of patients with IBD and reference individuals from the general population matched 1:1 to each patient by sex, age, birth year and place of residence.
| IBD | UC | CD | Reference [IBD overall] | IBD [no matched comparator] | |
|---|---|---|---|---|---|
| Total | 41 880 | 29 030 | 12 850 | 41 880 | 27 361 |
| Sex | |||||
| Female | 22 802 [54.4%] | 15 279 [52.6%] | 7523 [58.5%] | 22 802 [54.4%] | 10 777 [39.4%] |
| Male | 19 078 [45.6%] | 13 751 [47.4%] | 5327 [41.5%] | 19 078 [45.6%] | 16 584 [60.6%] |
| Age at first diagnosis [years] | |||||
| Mean [SD] | 50.4 [17.5] | 51.1 [17.4] | 49.0 [17.6] | 50.5 [17.4] | 28.2 [12.9] |
| Median [IQR] | 50.5 [36.4–63.9] | 51.1 [37.1–64.5] | 49.2 [34.4–62.6] | 50.6 [36.5–64.0] | 25.6 [18.6–35.8] |
| Range, min–max | 1.1–98.2 | 1.4–95.9 | 1.1–98.2 | 1.3–97.0 | 0.4–96.1 |
| <18 | 506 [1.2%] | 295 [1.0%] | 211 [1.6%] | 460 [1.1%] | 6263 [22.9%] |
| 18 to <40 | 12 545 [30.0%] | 8403 [28.9%] | 4142 [32.2%] | 12 508 [29.9%] | 16 147 [59.0%] |
| 40 to <60 | 15 474 [36.9%] | 10 779 [37.1%] | 4695 [36.5%] | 15 481 [37.0%] | 4347 [15.9%] |
| ≥60 | 13 355 [31.9%] | 9553 [32.9%] | 3802 [29.6%] | 13 431 [32.1%] | 604 [2.2%] |
| Year of first IBD diagnosis | |||||
| 1969–1976 | 251 [0.6%] | 170 [0.6%] | 81 [0.6%] | 317 [1.2%] | |
| 1977–1990 | 2784 [6.6%] | 1837 [6.3%] | 947 [7.4%] | 4245 [15.5%] | |
| 1991–2002 | 11 118 [26.5%] | 7909 [27.2%] | 3209 [25.0%] | 11 331 [41.4%] | |
| 2003–2016 | 27 727 [66.2%] | 19 114 [65.8%] | 8613 [67.0%] | 11 468 [41.9%] | |
| Year of IBD index date | |||||
| 1969–1976 | 3 [0.0%] | 2 [0.0%] | 1 [0.0%] | 3 [0.0%] | 114 [0.4%] |
| 1977–1990 | 1677 [4.0%] | 1065 [3.7%] | 612 [4.8%] | 1677 [4.0%] | 3448 [12.6%] |
| 1991–2002 | 11 017 [26.3%] | 7805 [26.9%] | 3212 [25.0%] | 11 017 [26.3%] | 11 662 [42.6%] |
| 2003–2016 | 29 183 [69.7%] | 20 158 [69.4%] | 9 025 [70.2%] | 29 183 [69.7%] | 12 137 [44.4%] |
| Country of birth | |||||
| Nordic | 38 822 [92.7%] | 27 053 [93.2%] | 11 769 [91.6%] | 38 820 [92.7%] | 25 908 [94.7%] |
| Non-Nordic | 3058 [7.3%] | 1977 [6.8%] | 1081 [8.4%] | 3060 [7.3%] | 1452 [5.3%] |
| Missing | 0 | 0 | 0 | 0 | 1 [0.0%] |
| Montreal Classification CD a | |||||
| Number classified since 1998 | 10 521 [81.9%] | ||||
| L1 [terminal ileum]/L3/LX [ileocolonic, not defined] | 7953 [61.9%] | ||||
| L2 [colon] | 2568 [24.4%] | ||||
| B1 [non-stricturing, non-penetrating] | 9410 [89.4%] | ||||
| B2 [stricturing] | 1111 [10.6%] | ||||
| B3 [penetrating] | 63 [0.6%] | ||||
| Perianal | 72 [0.7%] | ||||
| Montreal Classification UC | |||||
| Number classified since 1998 | 24 425 [84.1%] | ||||
| E1 [ulcerative proctitis]/E2 [left sided UC] | 11 546 [39.8%] | ||||
| E3 [extensive UC]/EX [extent not defined] | 15 064 [51.9%] | ||||
| Extraintestinal manifestations * | |||||
| Number classified since 1998 | 34 946 [83.4%] | 24 425 [84.1%] | 10 521 [81.9%] | 18 378 [67.2%] | |
| Primary sclerosing cholangitis [PSC] | 358 [1.0%] | 298 [1.2%] | 60 [0.6%] | 303 [1.6%] | |
| Other extraintestinal manifestations | 2678 [7.7%] | 1640 [6.7%] | 1038 [9.9%] | 996 [5.4%] | |
| History of colorectal cancer in first-degree relative | |||||
| Yes | 290 [0.7%] | 224 [0.8%] | 66 [0.5%] | 328 [0.8%] | 85 [0.3%] |
| Number of previous endoscopies at baseline | |||||
| 0 | 0 | 0 | 0 | 0 | 0 |
| 1 | 8762 [20.9%] | 5313 [18.3%] | 3449 [26.8%] | 22 673 [54.1%] | 7804 [28.5%] |
| 2 | 13 783 [32.9%] | 9384 [32.3%] | 4399 [34.2%] | 13 089 [31.3%] | 9903 [36.2%] |
| ≥3 | 19 335 [46.2%] | 14 333 [49.4%] | 5002 [38.9%] | 6118 [14.6%] | 9654 [35.3%] |
| Inflammatory status at index date | |||||
| Low histology score | 5197 [12.4%] | 3227 [11.1%] | 1970 [15.3%] | 2726 [10.0%] | |
| High histology score | 36 683 [87.6%] | 25 803 [88.9%] | 10 880 [84.7%] | 24 635 [90.0%] | |
| SnoMed normal mucosa codea | 10 077 [24.1%] | 6 401 [22.0%] | 3 676 [28.6%] | 22 088 [52.7%] | 5738 [21.0%] |
| SnoMed inflammation codea | 16 925 [40.4%] | 12 226 [42.1%] | 4699 [36.6%] | 4330 [10.3%] | 10 935 [40.0%] |
| Colon surgery at baseline | |||||
| Resection of the colon | 2483 [5.9%] | 453 [1.6%] | 2030 [15.8%] | 2541 [6.1%] | 1868 [6.8%] |
| Other bowel surgery | 1014 [2.4%] | 464 [1.6%] | 550 [4.3%] | 1634 [3.9%] | 642 [2.3%] |
| IBD therapy exposure at baseline | |||||
| Corticosteroids | 13 251 [31.6%] | 8856 [30.5%] | 4395 [34.2%] | 5620 [13.4%] | 5320 [19.4%] |
| 5-ASA | 16 032 [38.3%] | 13 226 [45.6%] | 2806 [21.8%] | 1054 [2.5%] | 6243 [22.8%] |
| Immunomodulators | 3336 [8.0%] | 1317 [4.5%] | 2019 [15.7%] | 570 [1.4%] | 1960 [7.2%] |
| Anti-TNF | 726 [1.7%] | 344 [1.2%] | 382 [3.0%] | 108 [0.3%] | 433 [1.6%] |
| Vedolizumab | 5 [0.0%] | 5 [0.0%] | 0 | 0 | 3 [0.0%] |
| Ustekinumab | 2 [0.0%] | 1 [0.0%] | 1 [0.0%] | 2 [0.0%] | 0 |
| Tofacitinib | 5 [0.0%] | 5 [0.0%] | 0 | 0 | 3 [0.0%] |
aSnoMed normal mucosa codes: M00100 or M00110; SnoMed inflammation codes: M41, M42, M43; M44, M45, M463 or M47.
Totals may not equal 100% based on missing or unknown data.
Abbreviations: IBD = inflammatory bowel disease, CD = Crohn’s disease, UC = ulcerative colitis, IQR = interquartile range, NA = not applicable.