Prognostic Analysis Of Critically Ill Patients With Acute Renal Injury Who Received Continuous Renal Replacement Therapy

Objective:Acute kidney injury(AKI)is also a common clinical problem encountered with critically ill patients and is generally related to an increase in morbidity and mortality..Numerous clinical studies indicate the relationships between AKI and long-term mortality,the development of chronic kidney disease(CKD),as well as the eventual progression to end-stage renal disease(ESRD).However,there are also some patients with a complete recovery from AKI may be confronted with adverse long-term outcomes.Existing analyses primarily focused on assessing in-hospital mortality in patients with AKI demanding continuous renal replacement therapy(CRRT).But the long-term outcomes of those peoples have not been concerned much,especially in China.The aim of this study was to evaluate the short-term(28d survival rate)and long-term(1-,3-and 5-year patient survival rates)mortality of critically ill patients with AKI who were on CRRT in an intensive care unit(ICU).And to investigate the association between various factors and outcomes.Meanwhile,renal function at discharge may be associated with increased mortality at follow-up,which has not been concerned much.The aim of this study was also aimed to clarify the relationship between renal function at discharge and long-term renal survival and overall long-term mortality of critically ill patients diagnosed with AKI and treated with CRRT in ICU.Methods:A total of 1720 patients with acute kidney injury treated with CRRT in ICU of the First Affiliated Hospital,College of Medicine,Zhejiang University from January 1,2008 to December 31,2013 were selected,and then 1165 patients were analyzed.The patients were divided into the death group(689 cases)and the survival group(476 cases)according to the 28d survival after CRRT treatment,and the 28d mortality was 59.14%(689/1165).The general data of the two groups were compared,and the risk factors for the 28d survival rate were identified by Logistic multivariate regression analysis.A total of 499 patients were survivors at discharge among those in the ICU,who followed up to their death to 30 September 2016 by telephone.96 patients were lack of follow-up.The remaining 403 patients in total were enrolled in this study.The general situation,the causes of AKI,and complications were analyzed.Patient survival curves and renal survival curves were generated by the Kaplan-Meier method and a log-rank test was employed to analyze statistical differences among groups.Cox proportional hazard survival model was adopted to evaluate independent predictors for long-term mortality.Results:There were 1720 patients who received CRRT in the ICU between 2008 and 2013.Among those,373 patients were excluded because they were on RRT or had received a kidney transplant before ICU admission and 182 patients were excluded because of incomplete data,and then 1165 patients were analyzed.Among those,68.2%(794/1165)was male and 31.8%(371/1165)was female.The age was 61.6±17.6(17-95)years old.The acute physiology and chronic health evaluation(APACHE)II score was 23±8,the simplified acute physiology score(SAPS ?)was56±18,median length of hospital stay was 18(7,35)d,median length of ICU stay was 8(4,17)d,median length of CRRT was 5(2,11)d,and the dose of CRRT was 51.5 ± 13.7mL.kg-1· h-1.The patients were divided into the death group(689 cases)and the survival group(476 cases)according to the 28d survival after CRRT treatment,and the 28d mortality was 59.1%.The age>65 years,the 24 h urine volume<400 mL,the use of mechanical ventilation,the application of vasopressors,the mean arterial pressure<80 mmHg,the platelet count<100 × 109/L,the bicarbonate radical<22 mmol/L,the lactic acid ?1.7 mmol/L,the total bilirabin ?100 ?mol/L,the serum creatinine<250 ?mol/L?the blood glucose<3.9 mmol/L,the acute physiology and chronic health evaluation(APACHE)II score>23 and the simplified acute physiology score(SAPS)II>56 of patients with acute kidney injury before CRRT in these two groups were significantly different(?2 = 10.376,11.596,85.674,103.017,86.318,41.626,9.862,86.269,30.228,28.691,13,664,212.194,232.712;all P<0.05).Logistic regression analysis showed that the age ? 65 years[hazard ratio(HR)=1.643,95%confidence interval(CI)(1.214,2.224)],the mean arterial pressure<80 mmHg[HR = 1.932,95%CI(1.417,2.633)],the platelet count<100 × 109/L[HR =1.968,95%CI(1.467,2.640)],the lactic acid>1.7 mmol/L[HR = 1.665,95%CI(1.226,2.262)],the total bilirubin>100 ?mol/L[HR = 2.263,95%CI(1.518,3.375)],the serum creatinine<250 ?ol/L[HR = 1.733,95%CI(1.269,2.366)],the blood glucose<3.9 mmol/L[HR = 3.365,95%CI(1.282,8.831)],the APACHE[II score>23[HR = 3.233,95%CI(2.325,4.495)]and the SAPS II score>56[HR = 3.058,95%CI(2.170,4.309)]were the risk factors of 28 d survival rate in patients with acute kidney injury after CRRT in ICU(all P<0.05).Of the 1165 patients who were diagnosed with AKI and were treated with CRRT in the ICU,666 patients(57.2%)died in the hospital and 96 patients were lack of follow-up.The remaining 403 patients in total were enrolled in this study.Among those,66.5%(268/403)was male,33.5%(135/403)was female,and the age was 60.8± 17.8(17-95)years old.Median length of CRRT was 6(1-149)d.The median APACHE II score was 23(12-63),the median SAPS ? score was 49.3± 15.5,and the median length of survival was 1133(1-2975)d.Sepsis(38.5%)was the primary cause of AKI,followed by decreased renal perfusion(28.8%)and surgical cause(15.9%).Respiratory diseases,hypertension and cardiovascular diseases occupy the greatest proportion in the most common comorbidities of 403 patients.A percentage of 26.6(107/403)was diagnosed with preexisting CKD.The cumulative survival rates were 64.3±2.4%in the first year,55.8±2.5%in the third years and 46.3±2.7%in the fifth years.And renal survival rates after hospital discharge in the first,third and fifth year were 74.4±2.3%,68.8±2.6%and 66.8±2.7%,respectively.According to the modification of diet in renal disease(MDRD)formula,the kidney function at discharge was arbitrarily defined with per eGFR category for the estimation of GFR.There were 135(33.5%),32(7.9%),51(12.7%),56(13.9%)and 129(32.0%)patients in the group defined as eGFR:>60mL/min,45-59mL/min,30-44mL/min,15-29mL/min and<15mL/min,respectively.Cox multivariate proportional hazard regression analysis identified that age,the causes of AKI(sepsis and decreased renal perfusion),a preexisting kidney disease,APACHE II score,SAPS II score,vasopressors and the eGFR<45mL/min/1.73m2 groups at discharge were all associated with decreased long-term patient survival(eGFR 30-44mL/min/1.73m2,HR 2.26[95%CI;1.36-3.74];eGFR 15-29mL/min/1.73m2,HR 4.89[95%CI,3.03-7.89];eGFR<15mL/min/1.73m2 and HR 5.67[95%CI,3.70-8.68]).Multivariate proportional hazard regression analysis also identified that age,a preexisting kidney disease,APACHE II score,mechanical ventilation(MV),eGFR<45ml/min/1.73 m2(eGFR30-44 mL/min/1.73m2(HR5.46,[95%CI,2.24-13.29],P<0.001),eGFR15-29 mL/min/1.73m2(HR6.76,[95%CI,2.81-16.30],P<0.001),eGFR<15mL/min/1.73m2(HR23.88,[95%CI,10.54-54.11],P<0.001)at discharge were all associated with decreased renal survival.Conclusions:1.The patients with AKI treated with CRRT in ICU had high mortality.In-hospital mortality was 57.2%and the 28d mortality was 59.1%.2.The age>65 years,the mean arterial pressure<80 mmHg,the platelet count<100×109/L,the lactic acid ? 1.7mmol/L,the total bilirubin ? 100?mol/L,the serum creatinine<250?mol/L,the blood glucose<3.9mmol/L,the APACHE II score>23 and the SAPS ? score>56 were the risk factors of the 28 d survival rate in patients with acute kidney injury after CRRT in ICU.3.The 1-,3-and 5-year patient survival rates were 64.3±2.4%,55.8±2.5%and 46.3 ±2.7%,respectively.4.In multivariate analysis,age,sepsis,decreased renal perfusion,preexisting kidney disease,APACHE II score,SAPS II score,vasopressors and eGFR<45mL/min/1.73m2 at discharge were independent factors for worse long-term patient survival.5.Renal survival rates after hospital discharge in the first,third and fifth year were 74.4±2.3%,68.812.6%and 66.812.7%,respectively.6.Age,preexisting kidney disease,APACHE II score,mechanical ventilation(MV)and eGFR<45mL/min/1.73m2 at discharge were also associated with worse renal survival.7.This study showed that impaired kidney function at discharge was shown to be an important risk factor affecting the long-term survival rates of critically ill patients with AKI.The eGFR<45mL/min/1.73m2 was an independent risk factor for decreased overall survival and renal survival.