Time to onset of gastrointestinal bleeding in the SUP‐ICU trial: A pre‐planned substudy

Background The aetiology and risk factors for clinically important gastrointestinal bleeding (CIB) in adult ICU patients may differ according to the onset of CIB, which could affect the balance between benefits and harms of stress ulcer prophylaxis (SUP). Methods We assessed the time to CIB in the Stress Ulcer Prophylaxis in the Intensive Care Unit (SUP‐ICU) trial. We assessed if associations between baseline characteristics including allocation to SUP and CIB changed during time in the ICU, specifically in the later (after day 2) compared to the earlier (first 2 days) period, using Cox models adjusted for SAPS II and allocation to SUP. Additionally, we described baseline characteristics and CIB episodes stratified by earlier/later/no CIB and 90‐day mortality status. Results Clinically important gastrointestinal bleeding occurred in 110/3291 (3.3%) patients after a median of 6 (interquartile range 2‐13) days; 25.5% of the episodes occurred early. Higher SAPS II was consistently associated with increased risk of CIB (hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.01‐1.05 in the earlier period vs HR 1.02, 95% CI 1.01‐1.03 in the later period; P = .37); university hospital admission was associated with decreased risk of earlier CIB (HR 0.30, 95% CI 0.14‐0.63); this significantly increased in the later period (to HR 0.85, 95% CI 0.53‐1.37; P = .02). Patients with later compared to earlier CIB received more transfusions and had more diagnostic/therapeutic procedures for CIB. Conclusions Clinically important gastrointestinal bleeding mostly occurred more than 2 days after randomization. University hospital admission was associated with significantly decreased risk of CIB in the earlier period only.