Figure 3

Kaplan–Meier curves of ICU survival differences in stratified analysis. In the subgroups of emergency admissions (a), patients with greater Acute Physiology and Chronic Health Evaluation II (APACHE II) scores (>8) (b) and surgical patients (c), mortality was significantly reduced during office hours (OH) compared with nighttime (NT). On the contrary, admission time did not correlate with ICU outcome in nonemergency admissions (d), the subset with low APACHE II scores (≤8) (e) and medical patients (f). LOS_icu, length of stay in the ICU. The dashed lines represented nighttime (NT) admissions, and the solid lines represented office hours (OH) admissions.