The natural history of Crohn's disease: need for initial and further resectional surgery
Bibliographic record
Abstract
Background: Crohn’s disease (CD) is characterised by a variable level of inflammatory activity over time, but underlying intestinal damage is thought to accumulate; ultimately necessitating resection surgery. Disease recurrence and inability of medical therapy to alter natural history may result in further resectional surgery. Furthermore some studies suggest that the risk of developing colorectal cancer (CRC) is elevated with guidelines recommending surveillance colonoscopy after 10 years of disease. Aims: To ascertain the need for initial and further resectional surgery and to determine the incidence of colorectal CRC in CD. Methods: The study is based on a prevalence cohort (1977–1992) of Sydney IBD patients fi rst described in 1995 that were longitudinally fol-lowed. CD patients were included if they were either diagnosed after 1977 or were yet to experience the studied events in 1977. Phenotyping was performed using the Montreal Classification. Cumulative incidences for first-, second resectional surgery and CRC (in patients with colonic involvement) were calculated by competing risk survival analysis using the statistical software R. Influence of disease extent, initial phenotype, age at diagnosis and year of diagnosis on cumulative incidences were also examined. Results: 377 patients (233 females, median age at diagnosis 29 years) were followed for a median of 14 years (5417 patient-years). Of these 168 (45%) had resection surgery. The cumulative risk of a first resection was 32% (95% CI 27%–37%) at 5 years, 43% (95% CI 37%–49%) at 10 years, and 53% (95% CI 46%–58%) by 15 years. Patients with colonic CD (phenotype L2) had a reduced risk of resection (hazard ratio [HR] 0.04; [95% CI 0.24–0.67, P < 0.001]). Stricturing disease (HR 3.93 [95% CI 2.51–6.15], P < 0.001) and penetrating disease (HR 5.18 [95% CI 3.39–7.91], P < 0.001) were each associated with an increased likelihood of surgery. There was no reduction in occurrence of fi rst resection by year of diagnosis. The cumulative incidence for a second resection was 20% (95% CI 14%–26%) 5 years, 36% (95% CI 28%–43%) 10 years and 42% (95% CI 33%–50%) 15 years after first surgery. None of the investigated factors were associated with an increased need for a second resectional surgery. Only 5 of 327 patients with colonic involvement developed CRC. The cumulative incidence of CRC was 1% (95% CI 0%–2%) at 10 years, 1% (95% CI 0%–2%) at 20 years and 2% (95% CI 0%–4%) at 30 years. Conclusion Of the 50% CD requiring surgery by 15 years of diagnosis, another 42% will require further resectional surgery by another 15 years indicating an inability to alter the natural history of CD. The incidence of CRC is low in colonic CD even on long term follow up. The yield of dysplasia screening is expected to be low if surveillance colonoscopy is recommended by follow up management guidelines.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".