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Timing of renal replacement therapy initiation by AKIN classification system

Tacyano T Leite1, Etienne Macedo2, Samuel M Pereira3, Sandro RC Bandeira3, Pedro HS Pontes3, André S Garcia3, Fernanda R Militão3, Irineu MM Sobrinho3, Livia M Assunção3 and Alexandre B Libório145*

Author Affiliations

1 Division of Nephrology, General Hospital of Fortaleza, Rua Ávila Goulart no. 900, 60175-295, Fortaleza, Brazil

2 Nephrology Department, University of São Paulo, Av. Dr. Eneas Carvalho de Aguiar no. 255, 05403-000, São Paulo, Brazil

3 Medical Course, UNIFOR, Av. Washington Soares no. 1321, 60811-905, Fortaleza, Brazil

4 Internal Medicine, Faculdade de Medicina, Universidade Federal do Ceará, Rua Alexandre Baraúna no. 900, 60430-160, Fortaleza, Brazil

5 Nephrology, Cancer Institute of Ceará, R. Papi Júnior no.1222, 60430-230, Fortaleza, Brazil

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Critical Care 2013, 17:R62  doi:10.1186/cc12593

Published: 2 April 2013

Abstract

Introduction

Previous studies using Acute Kidney Injury Network (AKIN)/RIFLE criteria to classify early initiation of renal replacement therapy (RRT) have defined it as the therapy started in less severe AKIN/RIFLE stages. Generally, these studies failed in demonstrating measurable benefits.

Methods

We compared RRT initiation in critically ill patients and defined early or late RRT in reference to timing after stage 3 AKIN was met: patients beginning RRT within 24 hours after acute kidney injury (AKI) stage 3 were considered early starters. AKIN criteria were evaluated by both urine output (UO) and serum creatinine (sCr) and patients with acute-on-chronic kidney disease were excluded. A propensity score methodology was used to control variables.

Results

A total of 358 critically ill patients were submitted to RRT. Only 150 patients with pure AKI at stage 3 were analyzed. Mortality was lower in the early RRT group (51.5 vs. 77.9%, P = 0.001). After achieving balance between the groups using a propensity score, there was a significant 30.5 (95% confidence interval [CI] 14.4 to 45.2%, P = 0.002) relative decrease of mortality in the early RRT group. Moreover, patients on the early RRT group had lower duration of mechanical ventilation, time on RRT and a trend to lower intensive care unit (ICU) length of stay.

Conclusions

For the first time, AKIN was used with UO criterion to evaluate early and late RRT. Using a time-based approach could be a better parameter to access the association between RRT initiation and outcomes in patients with AKI.