Short- and long-term outcomes of intensive care patients with acute kidney disease

BACKGROUND: Acute kidney disease (AKD) is a proposed definition for acute kidney injury (AKI) lasting 7 days or longer. Little has been reported regarding characteristics of patients with AKD and their short- and long-term outcomes. We describe the epidemiology and risk factors for AKD and outcomes following AKD. METHODS: This retrospective observational cohort study identified patients aged 16 or older admitted to the Glasgow Royal Infirmary and Queen Elizabeth University Hospital intensive care units (ICUs) in Scotland between 1st July 2015 and 30th June 2018. Baseline serum creatinine and subsequent values were used to identify patients with de-novo kidney injury (DNKI). Patients with recovery prior to day 7 were classified as AKI; recovery at day 7 or beyond was classified as AKD. Outcomes were in-hospital and long-term mortality, and proportion of major adverse kidney events (MAKEs). Multivariable logistic regression was used to identify risk factors for AKD. A Cox proportional hazards model was used to identify factors associated with long-term outcomes. FINDINGS: Of the 5,334 patients admitted to ICU who were assessed for DNKI, 1,620 (30·4%) suffered DNKI and of these, 403 (24·9%) met AKD criteria; 984 (60·7%) were male and the median age was 60·0 (IQR=48·0–72·0). Male sex, sepsis and lower baseline estimated glomerular filtration rate (eGFR) were associated with development of AKD. In-ICU (16·1%vs6·2%) and in-hospital (26·1%vs11·6%) mortality rates were significantly higher in AKD patients than AKI patients. Long-term survival was not different for AKD patients (HR=1·16; p-value=0·261) but AKD was associated with subsequent MAKEs (OR=1·25). INTERPRETATION: One in four ICU patients with DNKI met AKD criteria. These patients had an increased risk of short-term mortality and long-term MAKEs. Whilst the trend for long-term survival was lower, this was not significantly different from shorter-term AKI patients. Patients with AKD during their ICU stay should be identified to initiate interventions to reduce risk of future MAKEs. FUNDING: No funding was associated with this study.