Acute kidney disease and long-term outcomes in critically ill acute kidney injury patients with sepsis: a cohort analysis

BACKGROUND: Acute kidney injury (AKI) is frequent during hospitalization and may contribute to adverse short- and long-term consequences. Acute kidney disease (AKD) reflects the continuing pathological processes and adverse events developing after AKI. We aimed to evaluate the association of AKD, long-term adverse renal function and mortality in a cohort of patients with sepsis. METHODS: We performed a retrospective analysis of adult patients with septic AKI admitted to the Division of Intensive Medicine of the Centro Hospitalar Lisboa Norte (Lisbon, Portugal) between January 2008 and December 2014. Patients were categorized according to the development of AKI using the Kidney Disease: Improving Global Outcomes (KDIGO) classification. AKI was defined as an increase in absolute serum creatinine (SCr) ≥0.3 mg/dL or by a percentage increase in SCr ≥50% and/or by a decrease in urine output to <0.5 mL/kg/h for >6 h. AKD was defined as presenting at least KDIGO Stage 1 criteria for >7 days after an AKI initiating event. Adverse renal outcomes (need for long-term dialysis and/or a 25% decrease in estimated glomerular filtration rate after hospital discharge) and mortality after discharge were evaluated. RESULTS: From 256 selected patients with septic AKI, 53.9% developed AKD. The 30-day mortality rate was 24.5% (n = 55). The mean long-term follow-up was 45.9 ± 43.3 months. The majority of patients experience an adverse renal outcome [n = 158 (61.7%)] and 44.1% (n = 113) of patients died during follow-up. Adverse renal outcomes, 30-day mortality and long-term mortality after hospital discharge were more frequent among AKD patients [77.5 versus 43.2% (P < 0.001), 34.1 versus 6.8% (P < 0.001) and 64.8 versus 49.1% (P = 0.025), respectively]. The 5-year cumulative probability of survival was 23.2% for AKD patients, while it was 47.5% for patients with no AKD (log-rank test, P < 0.0001). In multivariate analysis, AKD was independently associated with adverse renal outcomes {adjusted hazard ratio [HR] 2.87 [95% confidence interval (CI) 2.0–4.1]; P < 0.001} and long-term mortality [adjusted HR 1.51 (95% CI 1.0–2.2); P = 0.040]. CONCLUSIONS: AKD after septic AKI was independently associated with the risk of long-term need for dialysis and/or renal function decline and with the risk of death after hospital discharge.