The clinical data used for conventional indications of initiating renal replacement therapy and for predicting the prognosis of critically ill patients with acute kidney injury / 中华急诊医学杂志

ABSTRACT

Objective To investigate the value of clinical data used for conventional indications of initiating renal replacement therapy (RRT) such as serum creatinine (SCr),blood urea nitrogen (BUN) and acute renal injury (AKI) stage and in estimating the prognosis of critically ill patients with AKI.Methods A retrospective analysis of 258 AKI adult inpatients treated with continuous renal replacement therapy (CRRT) in ICU from Jan.2011 to Jan.2015.According to the outcomes,all subjects were divided into survival group (n =104)and death group (n =154).The general condition,AKI causes,results of renal function (urine output,SCr,BUN and AKI stage),homeostasis (acid-base balance and electrolyte level),severity of disease (APACHE Ⅱ score and SOFA score) and others were compared between two groups.Additionally,risk factors for the prognosis of critically ill patients with AKI were screened by the multivariate Cox's proportional hazard models and the receiver operating characteristic (ROC) curve.Results There were no significant differences in gender,age,primary disease,AKI causes,APACHE Ⅱ score,renal function (urine output,SCr,BUN and AKI stage),serum potassium level and phosphorus level between two groups before CRRT (P ＞ 0.05),but more patients in death group had severe sepsis (31.17％ vs.19.23％,P =0.033),lower pH value [(7.27 ±0.34)vs.(7.41 ±0.34),P =0.024] and higher level of lactate [(3.97 ±2.87) vs.s (2.64 ± 2.30),P =0.006].After the analysis with multivariate Coxg proportional hazard models,it was found that the levels of serum phosphorus (P =0.043) and lactate (P =0.009) were the independent risk factors for prognosis of critically ill patients with AKI,and other conventional indications for initiating RRT such as SCr,BUN,AKI stage,urine output,pH,bicarbonate level or potassium level were not closely associated with the prognosis of patients (P ＞ 0.05).Therefore,a composite of these six variables (pH,bicarbonate level,phosphorus level,potassium level,urine output and AKI stage) was analyzed.According to the analysis result of ROC curve,the diagnostic value of combined six different variables in predicting in-hospital mortality of AKI patients [area under the curve (AUC) 0.669,95％ CI0.577-0.762] was almost as high as that of lactate (AUC0.683,95％ CI0.590-0.777),and significantly higher than SCr (AUC0.460,95％ CI0.358-0.562),BUN (AUC0.469,95％ CI0.366-0.571).Conclusions This composite of six different variables is more useful than any other conventional indications for initiating RRT in predicting post-AKI mortality.As a result,a composition of six different variables should be considered rather than any single variable alone for indication of initiating RRT in critically ill patients with AKI.