PTU-010 Prevalence and phenotype of IBD across primary and secondary care: implications for colorectal cancer surveillance
Bibliographic record
Abstract
Introduction Patients diagnosed with colonic IBD have increased risk of colorectal cancer (CRC). Colonoscopic surveillance reduces the risk of CRC-associated death through early detection; national/international guidelines recommend chromoendoscopy. We aimed to assess the burden of IBD in primary care unknown to our service and to identify patients eligible for surveillance. Methods We conducted a population-based observational study across primary and secondary care to evaluate the incidence/prevalence of IBD in our catchment. We identified cases from primary care using searches of practice databases and in secondary care using searches of hospital records. Case inclusion required a specialist diagnosis of ulcerative colitis (UC), Crohn’s disease (CD) or IBD unclassified. IBD was phenotyped according to the Montreal Classification and patients under the age of 75 years, who had been diagnosed with IBD with colonic disease involvement for more than 10 years, were deemed eligible for colonoscopic surveillance. Results Patients from 48/49 GP practices within our catchment were included. We identified 3690 patients with IBD living within our catchment of which 12% (875/3,690) were unknown to any local secondary care service. Overall, UC prevalence was 453/100 000 people (95% confidence interval 433–474), Crohn’s disease prevalence was 311/100 000 (95% CI 293–327), and IBD unclassified prevalence was 44/100 000 (95% CI 38–51). Patients managed solely in primary care, compared with those in secondary care, were older (mean age 60.9 vs 56.2 years, p<0.0001) and had longer disease duration (20.3 vs 14.2 years, p<0.0001). The proportion of UC out of total IBD was higher in primary care (69% vs. 58%, p<0.0001). A higher proportion of IBD patients in primary care than secondary care had undergone a colectomy (17% vs 5%, p<0.0001). Overall, 13% (388/2,815) patients known to secondary care and 29% (257/875) of patients unknown to any secondary care services were eligible for colonoscopic surveillance, equivalent to approximately one colonoscopy list per week. Conclusions We report one of the highest prevalence rates of IBD in Western Europe (1 in 124 patients). 12% of patients living in our immediate catchment area were unknown to our service; a third of these were eligible for colonoscopic colorectal cancer surveillance. Effective colorectal cancer surveillance programmes in IBD must target primary-care populations and not just known secondary care populations.
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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 | 0.002 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".