The Effect Of Glucocorticoids On Serum Cystatin C In Identifying Acute Kidney Injury

BackgroundThe therapeutic outcome of acute kidney injury(AKI)is unsatisfactory as the initiation of effective treatments are started relatively late after a noticeable elevation in serum creatinine(SCr).Serum cystatin C(sCysC)may be superior to SCr in early detecting a minimal change in the glomerular filtration rate.However,many studies have shown that sCysC levels are affected by glucocorticoids.However,it remains undefined whether glucocorticoids influence sCysC to detect AKI in critically ill patients.This study aimed to assess the effect of glucocorticoids on the performance of sCysC in detecting AKI in critically ill patientsMethodsA prospective observational study was undertaken in the general intensive care unit(ICU)of Guangdong Provincial People’s Hospital from October 2014 to December 2017.All serum samples for determining SCr,sCysC,and serum albumin were collected at ICU admission.SCr was measured at least once a day as a part of routine clinical care during ICU hospitalization.According to whether the patients accepted glucocorticoids treatment within 5 days before admission to the ICU,we divided the patients into glucocorticoids users and non-users.The patients’ baseline clinical data and the information of previous glucocorticoids administration within 5 days before entering ICU were prospectively collected.Established AKI and later-onset AKI were diagnosed if patients reached the KDIGO criteria at ICU admission or within 1 week after ICU admission,respectively.The bivariate correlation analysis and multivariable linear regression analysis was used to assess the relationship between sCysC and other variables.Then,we used the propensity score matching to eliminate the potential confounders and selection biases caused by nonrandomized in this study.Patients were divided into four groups based on accumulated doses of glucocorticoids within 5 days before admission to ICU:Group I(non-users),Group Ⅱ(Omg<prednisone ≤50mg),Group Ⅲ(50mg<prednisone≤150mg),Group Ⅳ(prednisone>150mg).We compared the levels of sCysC and its performance in detecting AKI in different groups.A receiver operating characteristic(ROC)curve analysis was generated,and the area under the curve(AUC)in each group was calculated to demonstrate the value of sCysC in detecting AKI.In this study,the ability of sCysC to diagnose AKI was evaluated using value of AUC that sCysC to detect the established AKI and the ability of sCysC to predicte AKI was evaluated using value of AUC that sCysC to detect the later-onset AKI.The difference between AUC in each group was calculated to access the impact of glucocorticoids on performance of sCysC in detecting AKI.ResultsA total of 240 patients received glucocorticoid medication within 5 days before ICU admission.Using propensity score matching,we successfully matched 240 glucocorticoid users with 960 non-users among 2716 patients.Before and after matching,the differences of sCysC levels between glucocorticoid users and non-users were both significant(P<0.05).The multiple linear regression analysis revealed that glucocorticoids were independently associated with sCysC.After matching,the group I had significantly lower sCysC levels than the group Ⅲ and group Ⅳ(P<0.05),but there were no significant differences in sCysC levels within different glucocorticoids recipient groups(P>0.05).Simultaneously,we did not find significant differences in the AUC between any two groups in the matched cohort(P>0.05).ConclusionsGlucocorticoids could induce an increase in sCysC levels.However,glucocorticoids did not have a statistically significant effect on the performance of sCysC in detecting AKI in critically ill patients.