A41 THE PRESENCE OF MELENA PREDICTS A PROXIMAL BLEEDING SITE AMONG PATIENTS WITH OBSCURE GASTROINTESTINAL BLEEDING: RESULTS OF A RETROSPECTIVE COHORT STUDY
Bibliographic record
Abstract
Melena is a hallmark symptom of upper gastrointestinal bleeding and results from the digestion of blood lost proximal to the ligament of Treitz in the majority of cases. However, whether melena also predicts bleeding in the proximal small intestine (SI) in the setting of obscure gastrointestinal bleeding (OGIB) is unknown. The objective of this study was to determine the predictive value of melena for determining the location of SI bleeding in OGIB. A retrospective cohort study was conducted of all patients who underwent capsule endoscopy (CE) for OGIB at London Health Sciences Centre between 2009 and March 2016. The presenting symptoms were recorded and categorized as melena or non-melena (ie. hematochezia and occult OGIB with iron deficiency anemia (IDA)). The primary outcome was diagnosis of a bleeding site between 0 - 50% SI transit time. Baseline demographics, comorbidities, medication usage, hemoglobin, and blood transfusion requirements were noted. The association between melena and proximal SI bleeding was determined using chi-square. 312 patients underwent CE for OGIB during the study period. Mean (SD) age was 63.9 years (15.4), and 55% were female. 36% of patients had melena, 14% had hematochezia, and 48% had only IDA. Blood transfusion was required within the past 12 months in 70% of patients and 14% of cases were performed as inpatients. The mean (SD) follow-up time was 16 months (24.1). The overall diagnostic rate was 45%, with angioectasias being the most common etiology (27%). 46% of patients with melena had a bleeding site within the proximal half of the SI compared to 31.3% who did not have melena (RR 1.47, p=0.01). The mean (SD) SI transit time for bleeding site was 21.2% (25.8) for those with melena and 34.7% (33.4) for those without (p=0.008). The probability of locating a bleeding site within the proximal half of the SI is 47% greater among OGIB patients with melena than those without. As such, antegrade double balloon enteroscopy without preceding CE may be warranted in this population. Melena vs Hematochezia+IDA+Melena&Hematochezia *Among those where a SI bleeding site is found. RR for prox 1/2 SI=1.47 (1.09–2.0, p=0.014). RR for prox 1/3 SI=1.35 (0.97–1.88, p=0.08) Schulich Research Opportunities Program
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".