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.