Patient characteristics, antibiotic use, and in‐hospital outcomes in patients with ischaemic colitis: A nationwide retrospective cohort study

Aim To describe patient characteristics, management and in‐hospital outcomes of ischaemic colitis, and to compare the rates of surgery and in‐hospital death between patients who did and did not receive antibiotics. Method We retrospectively identified hospital admissions for ischaemic colitis between April 2016 and March 2023 from the Diagnosis Procedure Combination inpatient database in Japan. We described the overall patient characteristics, management practices and outcomes, which were stratified by antibiotic use. The primary outcome was a composite of receipt of surgery and in‐hospital mortality. We examined the association between antibiotic use within the first 2 days of admission and the primary outcome occurring on or after day 3 of hospitalization using multivariable logistic regression analyses. Results Among 111,750 eligible cases, 36.2% received antibiotics within the first 2 days of admission. Of them, 0.9% underwent surgery and 1.3% died during hospitalization. The primary outcome occurred in 2.1% of cases in the overall cohort (≤2 days: 0.6%; ≥3 days: 1.5%) and in 1.0% of cases who did not receive (≤2 days: 0.2%; ≥3 days: 0.8%) and 4.2% of cases who received antibiotics (≤2 days: 1.5%; ≥3 days: 2.7%). After covariate adjustment, antibiotic use was associated with higher odds of the primary composite outcome (adjusted odds ratio 1.98, 95% confidence interval: 1.77–2.21). Conclusion The surgical rate and in‐hospital mortality in ischaemic colitis were lower than previously reported. Antibiotic use was associated with higher odds of surgery and in‐hospital mortality; however, this finding should be interpreted cautiously, given potential unmeasured confounding.