Prediction model for successful liberation from continuous renal replacement therapy in patients with acute kidney injury: development and temporal validation.

BACKGROUND: The optimal timing of liberation from continuous renal replacement therapy (CRRT) in adults with acute kidney injury (AKI) remains uncertain. This study developed and temporally validated a model for predicting successful 7-day liberation after a planned CRRT discontinuation attempt and compared its performance with urine output and serum creatinine (SCr)-based indices. METHODS: This single-center retrospective cohort included 447 adults with AKI who underwent a first planned CRRT discontinuation attempt between 2019 and 2024. Successful liberation was defined as survival without kidney replacement therapy (KRT) for 7 consecutive days after CRRT discontinuation. Patients treated in 2019-2022 formed the development cohort (n = 304), and those treated in 2023-2024 formed the temporal validation cohort (n = 143). Six prespecified predictors-Sequential Organ Failure Assessment (SOFA) score, sepsis-associated AKI, preceding 24-h urine output, relative SCr decline over the preceding 24 h, time-weighted mean arterial pressure (MAP), and vasoactive drug use-were entered into a multivariable logistic regression model. Multiple imputation, bootstrap optimism correction, calibration assessment, Brier score, decision curve analysis, and sensitivity analyses were performed. RESULTS: Overall, 241 patients (53.91%) achieved successful 7-day liberation. The optimism-corrected area under the receiver operating characteristic curve (AUC) in the development cohort was 0.860 (95% confidence interval [CI], 0.817-0.900), and the temporal validation AUC was 0.853 (95% CI, 0.785-0.913). In temporal validation, the Brier score was 0.156 (95% CI, 0.123-0.192), calibration intercept was -0.225 (95% CI, -0.648 to 0.198), and calibration slope was 0.984 (95% CI, 0.654-1.313). At the fixed development-derived threshold of 0.529, sensitivity was 84.21% and specificity was 71.64%. The full model outperformed urine output alone and SCr decline alone, whereas its AUC did not differ significantly from the combined urine output plus SCr model. CONCLUSION: This model provides individualized 7-day liberation risk estimates after standard CRRT discontinuation criteria and checklist completion. It is intended as an adjunctive risk-stratification tool for experienced clinicians and should not replace clinical judgment. Prospective multicenter external validation, local recalibration when needed, and clinical impact evaluation are warranted before implementation.