Acute medicine & surgery
Association Between Hour-by-Hour ICU Admission Timing and 24-h Mortality: A Single-Center Retrospective Observational Study
By Shirakawa K, Katsura Y, Watanabe H and 2 others.
Abstract
Aim
Prior studies of ICU admission timing often use broad categories (day vs. night), potentially masking hour-level effects. We examined hour-by-hour ICU admission timing and mortality, with attention to nighttime periods and routine handovers.
Methods
We conducted a single-center retrospective observational study in a closed ICU with 24/7 on-site intensivist coverage, using prospectively registered data from the Japanese Intensive Care Patient Database. Adults (≥ 18 years) admitted to the E-ICU between April 2017 and July 2025 were included. Admission hour (0-23) was modeled as a continuous exposure using restricted cubic splines (reference 14:00). The primary outcome was 24-h mortality and the secondary outcome was ICU mortality. Multivariable logistic regression was adjusted for demographics, APACHE II, invasive mechanical ventilation at admission, comorbidities, diagnostic categories, admission source, and post-cardiac arrest status. Bootstrap resampling was used to estimate 95% confidence intervals. Additional analyses examined handover, nighttime, and 24-h periodic patterns.