Outcome‐specific risk factors for dehydration and acute kidney injury readmission after ileostomy: A US National Cohort Study, 2016–2022

AIM: Single-centre pathways have reduced dehydration and acute kidney injury (AKI)-specific readmission after ileostomy from 17%-28% to single-digit rates, but whether these gains translated nationally is unknown. We examined how discharge destination relates to outcome-specific readmission, quantified 30-day readmission rates and encounter costs from 2016 to 2022 and identified risk factors at the population level. METHOD: Retrospective cohort study using the United States Nationwide Readmissions Database (NRD, 2016-2022). Adults undergoing ileostomy creation were included. The primary outcome was 30-day readmission for dehydration or AKI. Survey-weighted multivariable logistic regression identified risk factors for composite readmission, with home-discharge effects compared between dehydration- and AKI-specific outcomes. Inflation-adjusted encounter costs were calculated. RESULTS: Among 189,829 patients (176,150 discharged alive), 24,024 were readmitted within 30 days (13.5%, 95% CI 13.3-13.7). Home discharge had opposing associations by outcome subtype. Dehydration-specific readmission increased (aOR 1.25) and AKI-specific readmission decreased (aOR 0.92, p < 0.001 for interaction). The strongest risk factors were extended length of stay >7 days (aOR 1.48), complicated diabetes (aOR 1.46) and age ≥ 65 years (aOR 1.46). Annual rates were stable (p for trend = 0.826). Readmission encounters totalled $1.51 billion in inflation-adjusted dollars. The principal-diagnosis lower-bound estimate was $0.40 billion. CONCLUSION: Home discharge had divergent associations by outcome subtype, identifying the post-discharge transition as a candidate for prospective intervention testing. Stagnant national rates over 7 years despite established prevention evidence, an income-dependent gradient and a graded rate across cumulative risk-factor burden together motivate prospective evaluation of risk-stratified discharge protocols incorporating community stoma-output monitoring.