Risk Prediction for Acute Kidney Injury in Acute Medical Admissions in the UK.

Abstract

Background: Acute Kidney Injury (AKI) is associated with adverse outcomes; therefore identifying patients who are at risk of developing AKI in hospital may lead to targeted prevention. Aim: We undertook a UK-wide study in acute medical units (AMUs) to define those who develop hospital-acquired AKI (hAKI); to determine risk factors associated with hAKI and to assess the feasibility of developing a risk prediction score. Design: Prospective multicentre cohort study across 72 acute medical units in the UK. Methods: Data collected from all patients who presented over a 24-hour period. Chronic dialysis, community-acquired AKI (cAKI) and those with fewer than two creatinine measurements were excluded. Primary outcome was the development of h-AKI. Results: 2,446 individuals were admitted to the 72 participating centres. 384 patients (16%) sustained AKI of whom 287 (75%) were cAKI and 97 (25%) were hAKI. After exclusions, chronic kidney disease (OR 3.08, 95% CI 1.96-4.83), diuretic prescription (OR 2.33, 95% CI 1.5-3.65), a lower haemoglobin concentration and elevated serum bilirubin were independently associated with development of hAKI. Multivariable model discrimination was only moderate (c-statistic 0.75).Conclusions: AKI in AMUs is common and associated with worse outcomes, with the majority of cases community acquired. Only a small proportion of patients develop hAKI. Prognostic risk factor modelling demonstrated only moderate discrimination implying that widespread adoption of such an AKI clinical risk score across all AMU admissions is not currently justified. More targeted risk assessment or automated methods of calculating individual risk may be more appropriate alternatives.