There are limited data about the epidemiology of acute kidney injury (AKI) in critically ill patients in Northern Ireland. The aim of this study was to examine AKI within 24 hours of ICU admission and its relation to outcomes (ICU mortality and hospital mortality).

A secondary analysis of prospectively collected data in the Intensive Care National Audit and Research Centre Case Mix Programme Database. The Case Mix Programme Database was interrogated and data extracted from 22,313 admissions to eight ICUs from 1999 to 2007. The presence of AKI was assessed within the first 24 hours after admission (early AKI) and classified according to the RIFLE criteria. Trends over time were described for the RIFLE categories, and outcomes of admissions in each category were summarised. Where available, information on the use of renal replacement therapy during the ICU stay was analysed.

Trends in early AKI changed little over time: 35.5% of patients sustained AKI (risk 13.5%, injury 11.1%, failure 9.8%, end-stage 1.2%) and 9% of patients received renal replacement therapy. Outcomes are presented in Table 1.

For the first time we have established the incidence of early AKI using the RIFLE criteria in Northern Ireland ICUs. This will inform renal service development in ICUs. The incidence of severe AKI is high relative to the rest of the UK 1 although it is low compared with the US 2. Mortality increases with severity of renal injury.