Predictive value of RIFLE classification on prognosis of critically ill patients with acute kidney injury treated with continuous renal replacement therapy

Backqround The optimal timinq to start continuous renaI replacement therapy （CRRT）for acute l‘idnev iniuⅣ（AKl）13atierlts has not been accuratelv established.The recently proposed risk,injurv,fa.1ure,Ioss,end—staqe kidrleisease（RIFLE）criteria for diaqnosis and classification of AKI mav provide a method for clinicians t0 decide the"013timaI timina"for startincl CRRT under uniform quidelines.The Dresent study aimed:（1）to analyze the correlation between RIFLE staqeat the start of CRRT and 90-day survival rate after CRRT start,（2）to further investigate the correlation of RlFLE staqewith the maliqnarlt kidney outcome in the 90-day survivors,and（3）to determiiFie the influence of the timing 0f CRRTdefined by RIFLE classification on the 90-day survival and maliclnant kidney outcome in 90-dav sun—vors.Methods A retrospective cohort analysis was performed on the data of 106 critically ill Datients wh AKI,treated whCRRT during a 6-year period in a university affiliated surgical intensive care unit（SlCU）.1nformatiorl such as sex,aqe,RIFLE staqe,Sepsis,sepsis-related organ fallure assessment（SOFA）score,number of orqan failures before CRRTCRRT time during SICU,survival,and kidney outcome conditions at 90 days after CRRT start was collected.Accordincl t0their baselire severity of AKI at the start of CRRT the patients were assiqned to three qrouDs accordinq tO the increasirlqseverity of RIFLE staqes:RIFLE-R（risk of renal dvsfunction,R）,RIFLE-l（iniury to the kidrlev,1）and RIFLE.F（fa.1ure ofkidnev function,F）using RIFLE criteria.The maIiclnant kidney outcome was classified as RIFLE—L（Ioss of kidnev furlclionL）or RIFLE-E（end-staqe kidney disease.E）using RlFLE criteria.The correlation between RIFLE stacle and 90—davsurvival rate was arialyzed among these three RlFLE-cateqorized groups.Additionally,the association between RIFLEstaqe and the maliqnant kidnev outcome（RlFLE-L+RIFLF—E）in the 90-day survivors was analyzed.Results Fifty-thtee of the overall 106 patients survived to 90 days after the start of CRRT There were 1 6,22 813d 68patients in RIFLE-R.RlFLE-I and RlFLE-F grouls respectively with correspondlnq 90-day survival rate of 75.0%（1 2/1 6）,63.6%（1 4/22）and 39.7%（27/68）(Ρ<0.01,compared among groups).The percentage of the malignant kidRey OUtcomeof 90-day survivors in the RIFLE-R,RIFLE-1,and RIFLE-F groups was 16.7%（2/12）,21.4%（3/14）arld 55.6%（15/27）,respectively（Ρ for trend<0.01）.After adiustmerlt for other baseline risk factors.the reIative risk(F}同for the 90.davmortality siqnificantly increased with baseline RlFLE stage.Patients in RIFLE-F had a hiqher只R Of 1.96(95%confiderlceinterval(C:1.06-3.621 than patients in RlFLE-1（RR:1.09,95%CI:O.55—2.15）compared wh Dalients in RlFLE-R（Pfortrend<0.01）.Similarly,baseline RlFLE stage also significantly correlated with the odds ratio（OR）for the mali.qnantkidnev outcome in 90-day survivors（Ρ for trend<O.05）.Ninety-day survivors in the RlFLE—F.qroup had a border‘liFiesiqnificantly hiqhest OR of 6.88（95%CI: 0.85-55.67）.Conclusions The RlFLE cIassificalion may be used to predict 90-day survival after startinci CRRT and the maliQnantkidney outcome of 90-day survivors in the oriticallVilI patients with AKl trealed with CRRT.Startinq CRRT oriOr t0 RlFLE-Fstaqe may be the optimal timina.Prospective,multi-center,randomized controlled trials are needed tO confirm itspredictive value in these patients.