Day of Arrival as a Determinant of Endoscopy Timing in Non-Variceal Upper Gastrointestinal Bleeding: A Natural-Experiment Cohort Study of Clinical Outcomes and Length of Stay

Abstract

Background/Objectives: Guidelines recommend endoscopy within 24 h in acute upper gastrointestinal bleeding, but observational studies are confounded by indication. We used the weekday endoscopy schedule of our centre as a natural experiment. Methods: We studied a retrospective cohort of adults undergoing endoscopy for non-variceal upper gastrointestinal bleeding at one tertiary emergency department from 2019 to 2025. Timing was urgent (<12 h), early (12 to 24 h) or elective (>24 h); the primary outcome was 30-day mortality. Friday or Saturday arrival served as an instrument for delay, and crude, multivariable, propensity-based and instrumental-variable estimates were compared. Results: Among 413 episodes in 387 patients, median time to endoscopy was 22.1 h, with 54.5% within 24 h. The groups did not differ on 24 recorded baseline variables or six risk scores. Thirty-day mortality was 5.3% (22 deaths), with no detectable difference by timing (4.2%, 3.9%, and 6.9%; p = 0.420; adjusted odds ratio, elective versus early: 1.42, 95% CI: 0.50 to 4.03). Rebleeding, repeat endoscopy, intensive care admission and a composite outcome were unrelated. Total stay was longer with delay (incidence rate ratio: 1.40, 95% CI: 1.14 to 1.73), while stay from endoscopy onward was not (1.05, 95% CI: 0.80 to 1.38), and each day of waiting added 1.03 days of admission (95% CI: 0.60 to 1.46). Friday or Saturday arrival raised the elective proportion from 33.7% to 87.8% without altering the measured severity. Conclusions: Delay beyond 24 h was associated with no detectable difference in outcomes, although the 22 deaths left a moderate effect possible. The additional bed-days equalled the wait itself, which arose after gastroenterology consultation.