%0 Journal Article
%T Comparison of RIFLE with and without urine output criteria for acute kidney injury in critically ill patients: a task still not concluded!
%A Jos¨¦ Lopes
%A Sofia Jorge
%J Critical Care
%D 2013
%I BioMed Central
%R 10.1186/cc11911
%X Ameen Abu-Hanna, Kama A Wlodzimirow, Marcus Schultz and Catherine SC BoumanWe agree with Lopes and Jorge that multivariate analysis should be attempted when testing whether RIFLESCr is associated with higher mortality than RIFLESCr+UO. Essentially the question is whether the group (hereafter G1) of patients with AKI based on the RIFLESCr criteria (regardless of UO) is at higher risk of death than the group (hereafter G2) classified as having AKI based on the UO criteria only. Additional analysis, not reported in [1], shows that out of admission type, age, gender, weight, Acute Physiology and Chronic Health Evaluation (APACHE) score, Simplified Acute Physiology Score (SAPS), cardiopulmonary resuscitation, and length of stay, only SAPS was a confounder. Before adjustment for SAPS, patients in G1 had 1.64 times the odds of dying than those in G2. After adjustment for SAPS, the OR was reduced to 1.45 (P = 0.0004), still confirming our findings, which are in agreement with those of the other study [3].The seeming contradiction between our findings and those of Lopes and colleagues [4] is easily explained by the significant differences in case mix. In our study, 48.6% of the RIFLESCr+UO AKI patients were classified as having AKI on the basis of the UO criteria only [1] versus 5.6% in the study by Lopes and colleagues [4]. Differences in case mix may be attributable to the different inclusion criteria, the Modification of Diet in Renal Disease (MDRD)-based estimation of baseline SCr in all patients in the previous study [4], which may overestimate AKI based on SCr [5], and the outcome definition. All of these are important factors to consider when comparing studies.AKI: acute kidney injury; AUROC: area under the receiver operator characteristic; OR: odds ratio; RIFLE: Risk Injury Failure Loss End-stage renal disease; RIFLESCr: RIFLE criteria based on the serum creatinine criteria only; RIFLESCr+OU: RIFLE criteria based on serum creatinine and urine output criteria; SAPS: S
%U http://ccforum.com/content/17/1/408