Development and validation of a temporal staging-based nomogram for 1-year mortality in sepsis-associated acute kidney injury.

BACKGROUND: Sepsis-associated acute kidney injury (SA-AKI) is a life-threatening condition with poor prognosis. However, due to significant inter-individual variability in disease progression, clinicians lack reliable tools to stratify patients based on long-term mortality risk. OBJECTIVE: This study explores how the timing of SA-AKI (early vs. late onset) affects survival, based on the latest ADQI consensus, and aims to build a simple nomogram to predict 1-year mortality. METHODS: A retrospective cohort study enrolled 422 SA-AKI patients (from 3273 sepsis patients) admitted to the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2024. Patients were stratified into early-onset SA-AKI(E-SA-AKI, within 48 hours of sepsis diagnosis) and late-onset SA-AKI (L-SA-AKI, 48 hours-7 days post-sepsis) groups, with a maximum 5-year follow-up. RESULTS: The study found that most SA-AKI cases were early-onset (E-SA-AKI vs. L-SA-AKI: 73% vs. 27%). The median age of patients was 65 years, with 72% males. The primary infection sources were abdominal (41.9%) and pulmonary/urinary (36.3%). The cumulative survival rates at 28 days, 90 days, 1 year, and 5 years were 50.5%, 44.8%, 38.9%, and 33.9%, respectively. Both short-term and long-term survival rates were significantly higher in E-SA-AKI patients than L-SA-AKI patients(all P < 0.001). Using LASSO and multivariable Cox regression analyses, a prognostic model was developed, identifying five independent predictors of one-year mortality:L-SA-AKI and septic shock as risk factors, while high albumin level, 28-day renal function recovery, and 48-hour lactate normalization as protective factors. The model's C-statistic (C-index)was 0.79, demonstrating good discrimination and calibration in both the training set [AUC (95% CI): 0.897(0.853-0.931)] and the validation set (AUC(95% CI): 0.909 [0.839-0.951)]. Decision curve analysis indicated favorable clinical utility. CONCLUSION: The timing of SA-AKI onset is a critical prognostic stratification indicator. A one-year mortality risk nomogram model constructed based on the temporal staging, septic shock, albumin level, 28-day renal function recovery status, and 48-hour lactate normalization provides important reference for clinical decision-making.