Acute kidney injury and 30-day unplanned cirrhosis readmissions: A nationwide Readmissions Database retrospective cohort study

30-day unplanned readmissions after hospitalization for liver cirrhosis are common. Acute kidney injury (AKI) may be associated with higher early readmission risk. Using the Nationwide Readmissions Database 2016 to 2017, we identified adults with an index cirrhosis admission from January through November by International Classification of Diseases Tenth Revision Clinical Modification (ICD-10-CM) codes. AKI was defined by N17.x during the index stay. Unplanned 30-day readmissions were identified after excluding planned readmissions and trauma-related hospitalizations. Survey-weighted multivariable logistic regression adjusted for patient, clinical, and hospital factors. Among 1,68,816 index admissions, AKI occurred in 25.6%. Overall, 25.0% had unplanned 30-day readmission, higher with AKI than without (26.0% vs 24.2%; absolute difference 1.8 percentage points). AKI was independently associated with readmission (adjusted odds ratio 1.10, 95% confidence interval 1.05-1.16). AKI admissions had longer length of stay (median 6 vs 4 days), higher inflation-adjusted charges ($58,507 vs $32,587), and nonhome discharge (34% vs 16%; all P < .001). Readmissions occurred at a median of 12 days and had 7.72% in hospital mortality. Ascites and chronic kidney disease were strong predictors. AKI was associated with readmission among patients without chronic kidney disease but not among those with it (interaction P < .001). AKI during the index admission was associated with unplanned 30-day readmission, although the association was modest in magnitude, and marked a high-risk cirrhosis population with greater resource use. Because of the observational, retrospective design, causality cannot be established.