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Critical Care

Open Access

Acute kidney injury according to RIFLE criteria in an ICU: incidence and mortality impact

  • AR Santana1,
  • FF Amorim1,
  • FB Soares1,
  • LG de Souza Godoy1,
  • L de Jesus Almeida1,
  • TA Rodrigues1,
  • G Menezes de Andrade Filho1,
  • TA Silva1,
  • JL de Souza1,
  • KCM Ogliari1,
  • PN FerreiraJr1,
  • APP Amorim1,
  • EB de Moura1,
  • JA de Araújo Neto1 and
  • M de Oliveira Maia1
Critical Care201317(Suppl 3):P30

Published: 19 June 2013


Acute kidney injury (AKI) is a very common condition in hospitalized patients, especially in ICUs. It is also closely related to adverse patient outcomes, mortality rates as high as three-quarters and as many as 13% need of renal support after hospital discharge. A systematic review demonstrated a close correlation between AKI according to the RIFLE criteria and mortality. The objective of this study was to evaluate the incidence of AKI according to the RIFLE criteria and the impact of each category on mortality in an ICU.


A retrospective cohort study was conducted with patients admitted to the adult ICU of Hospital Santa Luzia, Brasilia, DF, Brazil, in the period of 6 months. Patients were categorized as Risk (R), Injury (I), Failure (F), or without AKI according to RIFLE criteria. Patients with a previous diagnosis of chronic kidney disease were excluded.


A total of 626 patients were included. Average age was 60 ± 20 years, 326 were male (50.8%), APACHE II was 9 ± 6, 67.1% (n = 326) were nonsurgical, and the mortality rate was 12.3% (n = 77). According to RIFLE criteria, 148 had AKI. Eighty-three patients were classified as R (13.3%, mortality rate of 21.7%), 43 as I (6.9%, mortality rate of 53.5%), and 22 patients as F (3.5%, mortality rate of 54.5%). The relative risk (RR) of death in patients classified as R was 2.72 (95% CI: 1.26 to 4.09), I was 11.27 (95% CI: 5.81 to 21.83), and F was 9.91 (95% CI: 4.14 to 23.94). Analyzing all patients with AKI, the RR of death was 11.22 (95% CI: 6.57 to 19.17). Eight (1.3%) patients underwent renal replacement therapy during ICU hospitalization, and mortality in these patients was 75% (RR: 23.11, 95% CI 4.58 to 116.71). Significant difference was observed in the Kaplan-Meier survival curves of the patients with or without AKI at 28 days (P = 0.00). See Figure 1.
Figure 1



AKI according to RIFLE criteria was associated with an increased mortality for all categories, mainly in patients with criteria to injury and acute kidney failure, and notably those who needed renal replacement therapy.

Authors’ Affiliations

Unidade de Terapia Intensiva Adulto do Hospital Santa Luzia, Asa Sul, Brasília, Brazil


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© Santana et al; licensee BioMed Central Ltd. 2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.