Clinical and resource burden of acute kidney injury among adults hospitalized with sepsis: a retrospective cross-sectional study

Acute kidney injury (AKI) is a frequent complication of sepsis and is associated with worse clinical outcomes. However, contemporary national estimates of its broader clinical and health-system burden, including discharge disposition, remain limited. We used a large nationally representative database to characterize the epidemiology and associated outcomes of AKI among adults hospitalized with sepsis in the United States. We conducted a cross-sectional study of adult sepsis hospitalizations in the 2022 National Inpatient Sample (NIS). AKI was identified using ICD-10-CM codes (N17.x) in any diagnosis position. Clinical outcomes included in-hospital mortality, mechanical ventilation, central venous catheter placement (marker of intensive care–level management), and in-hospital dialysis. Resource outcomes included length of stay, total hospital charges, and discharge disposition. Survey-weighted logistic and gamma regression models were used to estimate adjusted odds ratios (aORs) and adjusted ratios of geometric means (aROMs), adjusting for demographic, socioeconomic, and Elixhauser comorbidity variables. Sensitivity analyses evaluated dialysis associations after excluding patients with pre-existing end-stage renal disease (ESRD) and assessed robustness of AKI definition using primary-diagnosis restriction. Among an estimated 2.96 million adult sepsis hospitalizations in 2022, 44.5% involved AKI. Compared with sepsis hospitalizations without AKI, those with AKI demonstrated higher unadjusted mortality (19.8% vs. 7.5%), greater use of mechanical ventilation (22.3% vs. 9.3%), and increased central venous catheter placement (10.1% vs. 5.8%). After adjustment, AKI remained strongly associated with in-hospital mortality (aOR 2.44; 95% CI 2.38–2.50), mechanical ventilation (aOR 2.66; 95% CI 2.60–2.72), central venous catheter placement (aOR 1.70; 95% CI 1.65–1.74), longer length of stay (aROM 1.33; 95% CI 1.32–1.34), and higher total hospital charges (aROM 1.50; 95% CI 1.48–1.52). AKI was also associated with lower likelihood of home discharge (26.0% vs. 43.8%) and greater transfer to post-acute care facilities (40.4% vs. 30.8%). In fully adjusted models, AKI was associated with lower odds of dialysis (aOR 0.73; 95% CI 0.70–0.76); however, exclusion of patients with pre-existing ESRD reversed this association (aOR 19.0; 95% CI 14.1–25.7), suggesting influence of administrative coding structure. Given potential misclassification of chronic dialysis status in administrative data, dialysis findings should be interpreted as exploratory. In a contemporary nationally representative cohort, AKI was common among adults hospitalized with sepsis and was independently associated with higher mortality, greater concurrent organ-support involvement, prolonged hospitalization, increased financial burden, and worse discharge disposition. Sensitivity analyses highlight the influence of chronic dialysis coding on dialysis outcomes and underscore the importance of cautious interpretation of administrative data. These findings support recognition of AKI as a high-risk prognostic phenotype within sepsis hospitalizations and emphasize its substantial recovery and health-system burden.