Clinical characteristics of patients with LGD for the discovery and validation cohorts
| Clinical characteristics of included patients with LGD | Discovery cohort | Validation cohort | Difference between groups |
| (n=249) | (n=211) | (P value) | |
| Gender | (n=249) | (n=211) | 0.276 |
| Female | 85 (34.1%) | 62 (29.4%) | |
| Male | 164 (65.9%) | 149 (70.6%) | |
| Median age at index LGD diagnosis (years) | 62.0 (IQR 53.5–69.0) | 58.0 (IQR 48.0–68.0) | 0.021 |
| Median duration of UC at index LGD diagnosis (years) | 22.0 (IQR 12.0–33.0) | 16.0 (IQR 6.0–27.0) | <0.001 |
| Colitis extent proximal to splenic flexure | 225/249 (90.4%) | 166/210 (79.0%) | 0.001 |
| Presence of concomitant PSC | 13/248 (5.2%) | 38/191 (19.9%) | <0.001 |
| Exposure to 5-aminosalicylates | (n=238) | (n=74) | 0.382 |
| None documented | 28 (11.8%) | 9 (12.2%) | |
| 0–10 years | 53 (22.3%) | 11 (14.9%) | |
| >10 years | 157 (66.0%) | 54 (73.0%) | |
| Exposure to immunomodulators | (n=237) | (n=75) | 0.354 |
| None documented | 171 (72.2%) | 48 (64.0%) | |
| 0–10 years | 43 (18.1%) | 19 (25.3%) | |
| >10 years | 23 (9.7%) | 8 (10.7%) | |
| Exposure to biological therapy | 9/236 (3.8%) | 1/76 (1.3%) | 0.282 |
| Morphology of index LGD | (n=247) | (n=205) | <0.001 |
| Polypoid | 142 (57.5%) | 133 (64.9%) | |
| Non-polypoid | 87 (35.2%) | 42 (20.5%) | |
| Invisible | 18 (7.3%) | 30 (14.6%) | |
| Visible index LGD size 10 mm or more | 79/248 (31.9%) | 68/202 (33.7%) | 0.684 |
| Location of index LGD | (n=243) | (n=209) | 0.001 |
| Distal to splenic flexure | 115 (47.3%) | 133 (63.6%) | |
| Proximal to splenic flexure | 128 (52.7%) | 76 (36.4%) | |
| Successful endoscopic resection of index LGD (judged by endoscopic criteria) | 209/249 (83.9%) | 139/207 (67.1%) | <0.001 |
| Multifocal LGD at index diagnosis | 61/249 (24.5%) | 37/211 (17.5%) | 0.069 |
| Previous indefinite for dysplasia | 12/249 (4.8%) | 9/210 (4.3%) | 0.785 |
| Presence of a colonic stricture | 8/249 (3.2%) | 2/210 (1.0%) | 0.098 |
| Scarring/tubular/shortened colon | 137/249 (55.0%) | 29/208 (13.9%) | <0.001 |
| Multiple postinflammatory polyps | 88/241 (36.5%) | 58/209 (27.8%) | 0.048 |
| Cumulative inflammation burden (CIB) score from 5 years preceding index LGD diagnosis | (n=177) 1.5 (IQR 0.0–3.0) | ||
| Maximum severity of histological active inflammation in any colonic segment at the same time or within previous 5 years of index LGD diagnosis | (n=247) | (n=207) | 0.006 |
| Quiescent | 105 (42.5%) | 66 (31.9%) | |
| Mild | 80 (32.4%) | 59 (28.5%) | |
| Moderate | 47 (19.0%) | 55 (26.6%) | |
| Severe | 15 (6.1%) | 27 (13.0%) | |
| Maximum severity of histological active inflammation in any colonic segment within 5 years after index LGD diagnosis | (n=227) | (n=207) | 0.003 |
| Quiescent | 117 (51.5%) | 75 (36.2%) | |
| Mild | 52 (22.9%) | 54 (26.1%) | |
| Moderate | 47 (20.7%) | 53 (25.6%) | |
| Severe | 11 (4.8%) | 25 (12.1%) | |
| Chromoendoscopy use | 202/245 (82.4%) | 148/208 (71.2%) | 0.004 |
| Median number of colonoscopies performed in surveillance follow-up | 4.0 (IQR 2.0–7.0) | 2.0 (IQR 1.0–4.0) | <0.001 |
| Median follow-up time after index LGD diagnosis (years) | 5.1 (IQR 2.2–8.5) | 3.1 (IQR 1.3–5.8) | <0.001 |
| Metachronous LGD on follow-up | (n=249) | (n=209) | <0.001 |
| None | 84 (33.7%) | 109 (52.2%) | |
| In same colonic segment | 38 (15.3%) | 31 (14.8%) | |
| In different segment | 127 (51.0%) | 69 (33.0%) | |
| Number of progressed to advanced neoplasia | 30/249 (12.0%) | 25/211 (11.8%) | 0.948 |
| Number of progressed to CRC | 18/249 (7.2%) | 15/211 (7.1%) | 0.96 |
| Colectomy surgery after LGD diagnosis | 50/249 (20.1%) | 38/211 (18.0%) | 0.001 |
Statistical significance required p<0.002 with Bonferroni multiple testing correction (bold values).
CIB score was defined as sum of average scores between each pair of surveillance episodes multiplied by the surveillance interval in years.
CRC, colorectal cancer; ; LGD, low-grade dysplasia; PSC, primary sclerosing cholangitis.