Different clinical outcomes in Crohn’s disease patients with esophagogastroduodenal, jejunal, and proximal ileal disease involvement: is L4 truly a single phenotype?
Bibliographic record
Abstract
Background: The Montreal classification defines L4 Crohn’s disease (CD) as any disease location proximal to the terminal ileum, which anatomically includes L4-esophagogastroduodenal (EGD), L4-jejunal, and L4-proximal ileal involvement. L4-jejunal disease was established to be associated with poor prognosis. However, the outcome of patients with L4-proximal ileal disease or L4-EGD remains to be clarified. Our study aimed to investigate whether the outcome differs among CD patients with L4-EGD, L4-jejunal, and L4-proximal ileal disease. Methods: In our retrospective cohort study, 483 patients with confirmed CD were included. The primary outcome was intestinal surgery. Demographic features and outcomes were compared among L4-EGD, L4-jejunal, and L4-proximal ileal disease. Results: Thirty-nine (8.1%) patients had isolated L4 disease, whereas 146 patients had L4 as well as concomitant L1, L2, or L3 disease. During a median follow up of 5.8 years, L4 patients were more likely to have intestinal surgeries compared to non-L4 patients (31% versus 16%, p < 0.001). The percentage of L4-jejunal patients who underwent surgery was higher than that of L4-proximal ileal (66% versus 28%, p < 0.001), and both of these subtypes of L4 were at higher risk for intestinal resection compared to L4-EGD patients (66% and 28% versus 9%, respectively, p < 0.001 and p < 0.05). On multi-variable analysis, L4-jejunal (HR 3.08; 95% CI 1.30–7.31) and L4-proximal ileal disease (HR 1.83; 95% CI 1.07–3.15) were independent predictors for intestinal resection. Conclusions: L4 disease had worse prognosis compared to non-L4 disease. Within L4 disease, phenotype of L4-jejunal and L4-proximal ileal disease indicated higher risk for intestinal surgery. It might be justified to further characterize the L4 phenotype of the Montreal classification into three specific subgroups including L4-EGD, L4-jejunal, and L4-proximal ileal disease, similar to the Paris classification of pediatric patients.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 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".