Can admission serum cystatin C level be an early marker subclinical acute kidney injury in critical care patients?

BACKGROUND: In critical care patients, the diagnosis of subclinical acute kidney injury (AKI) might be difficult with measurements of serum creatinine and estimated glomerular filtration rate (eGFR). Their 'sensitive kidneys' can easily be affected from sepsis, underlying diseases, medications and volume status and if they can be detected earlier, some preventive measures might be taken. In this study we aimed to determine whether admission serum cystatin C (sCys-C) and other clinical parameters can identify subclinical AKI in medical intensive care unit (ICU) patients with normal creatinine-based eGFR at admission. METHODS: A prospective cohort study, performed in an adult ICU of a university hospital between January 2008 and March 2013. The blood samples were obtained within the first 24-48 hours of admission and sCys-C levels were analyzed with particle-enhanced immunonephelometric assay. AKI development was assessed according to RIFLE criteria. The cutoff value of sCys-C for the prediction of AKI was determined with receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 72 patients were included in the study and 19 (26%) of them developed AKI. Among the patients with AKI admission sCys-C levels were significantly higher when compared with non-AKI patients (1.06 ± 0.29 vs. 0.89 ± 0.28 respectively, p = 0.026). With ROC curve analysis, the threshold level for sCys-C was 0.94 mg/L with 63% sensitivity and 66% specificity [AUC: 0.67, p = 0.026]. With logistic regression analysis 'high sCys-C levels at admission' (OR = 4.73; 95%CI 1.03-21.5, p = 0.044) was found as one of the independent variables for the prediction of AKI development, in addition to 'being intubated before ICU admission' (OR = 10.2; 95%CI 1.72-60.4, p = 0.01) and 'hypotension during ICU follow-up' (OR = 12.3; 95%CI 2.5-60.1, p = 0.002). CONCLUSION: In this cohort of patients, a high sCys-C level at admission was found to be a predictor of subclinical AKI arising during their ICU stay. If supported with further studies, it might be used to provide more accurate and earlier knowledge about renal dysfunction and to take appropriate preventive measures.

Clinical Outcomes and Independent Risk Factors for 90-Day Mortality in Critically Ill Patients with Respiratory Failure Infected with SARS-CoV-2: A Multicenter Study in Turkish Intensive Care Units.

BACKGROUND: There are limited data on the long-term outcomes of COVID-19 from different parts of the world. AIMS: To determine risk factors of 90-day mortality in critically ill patients in Turkish intensive care units (ICUs), with respiratory failure. STUDY DESIGN: Retrospective, observational cohort. METHODS: Patients with laboratory-confirmed COVID-19 and who had been followed up in the ICUs with respiratory failure for more than 24 hours were included in the study. Their demographics, clinical characteristics, laboratory variables, treatment protocols, and survival data were recorded. RESULTS: A total of 421 patients were included. The median age was 67 (IQR: 57-76) years, and 251 patients (59.6%) were men. The 90-day mortality rate was 55.1%. The factors independently associated with 90-day mortality were invasive mechanical ventilation (IMV) (HR 4.09 [95% CI: [2.20-7.63], P < .001), lactate level >2 mmol/L (2.78 [1.93-4.01], P < .001), age ≥60 years (2.45 [1.48-4.06)], P < .001), cardiac arrhythmia during ICU stay (2.01 [1.27-3.20], P = .003), vasopressor treatment (1.94 [1.32-2.84], P = .001), positive fluid balance of ≥600 mL/day (1.68 [1.21-2.34], P = .002), PaO2/FiO2 ratio of ≤150 mmHg (1.66 [1.18-2.32], P = .003), and ECOG score ≥1 (1.42 [1.00-2.02], P = .050). CONCLUSION: Long-term mortality was high in critically ill patients with COVID-19 hospitalized in intensive care units in Turkey. Invasive mechanical ventilation, lactate level, age, cardiac arrhythmia, vasopressor therapy, positive fluid balance, severe hypoxemia and ECOG score were the independent risk factors for 90-day mortality.