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The data presented in this article are related to the research article entitled "The Diagnostic Value of Rescaled Renal Biomarkers Serum Creatinine and Serum Cystatin C and their Relation with Measured Glomerular Filtration Rate" (Pottel et al. (2017) [1]). Data are presented demonstrating the rationale for the normalization or rescaling of serum cystatin C, equivalent to the rescaling of serum creatinine. Rescaling biomarkers brings them to a notionally common scale with reference interval [0.67-1.33]. This article illustrates the correlation between rescaled biomarkers serum creatinine and serum cystatin C by plotting them in a 2-dimensional graph. The diagnostic value in terms of sensitivity and specificity with measured Glomerular Filtration Rate as the reference method is calculated per age-decade for both rescaled biomarkers. Finally, the interchangeability between detecting impaired kidney function from renal biomarkers and from the Full Age Spectrum FAS-estimating GFR-equation and measured GFR using a fixed and an age-dependent threshold is shown.

Background: Although serum cystatin C (sCysC), urinary N-acetyl-β-D-glucosaminidase (uNAG), and urinary albumin/creatinine ratio (uACR) are clinically available, their optimal combination for acute kidney injury (AKI) detection and prognosis prediction remains unclear. We aimed to assess the discriminative abilities of these biomarkers and their possible combinations for AKI detection and intensive care unit (ICU) mortality prediction in critically ill adults., Methods: A multicenter, prospective observational study was conducted in mixed medical-surgical ICUs at three tertiary care hospitals. One thousand eighty-four adult critically ill patients admitted to the ICUs were studied. We assessed the use of individual biomarkers (sCysC, uNAG, and uACR) measured at ICU admission and their combinations with regard to AKI detection and prognosis prediction., Results: AUC-ROCs for sCysC, uNAG, and uACR were calculated for total AKI (0.738, 0.650, and 0.683, respectively), severe AKI (0.839, 0.706, and 0.771, respectively), and ICU mortality (0.727, 0.793, and 0.777, respectively). The panel of sCysC plus uNAG detected total and severe AKI with significantly higher accuracy than either individual biomarkers or the other two panels (uNAG plus uACR or sCysC plus uACR). For detecting total AKI, severe AKI, and ICU mortality at ICU admission, this panel yielded AUC-ROCs of 0.756, 0.863, and 0.811, respectively; positive predictive values of 0.71, 0.31, and 0.17, respectively; and negative predictive values of 0.81, 0.97, and 0.98, respectively. Moreover, this panel significantly contributed to the accuracy of the clinical models for AKI detection and ICU mortality prediction, as measured by the AUC-ROC, continuous net reclassification index, and incremental discrimination improvement index. The comparable performance of this panel was further confirmed with bootstrap internal validation., Conclusions: The combination of a functional marker (sCysC) and a tubular damage marker (uNAG) revealed significantly superior discriminative performance for AKI detection and yielded additional prognostic information on ICU mortality.

Background: Frail individuals are at increased risk for poor outcomes, including adverse drug events. Kidney function is often compromised in frailty and is a key consideration in medication choice and dosing; however, creatinine-based measures of kidney function may be biased in frail individuals., Study Design: Observational study., Setting & Participants: 4,987 community-dwelling older men and women with complete data who participated in visit 5 of the Atherosclerosis Risk in Communities (ARIC) Study (2011-2013)., Predictors: Kidney measures included glomerular filtration rate (GFR) estimated using serum creatinine (eGFR cr ) and serum cystatin C level (eGFR cys ) and urine albumin-creatinine ratio., Outcome: Frailty, defined using established criteria of 3 or more frailty characteristics (weight loss, slowness, exhaustion, weakness, and low physical activity)., Results: 341 (7%) participants were classified as frail, 1,475 (30%) had eGFR cr <60mL/min/1.73m 2 , 2,480 (50%) had eGFR cys <60mL/min/1.73m 2 , and 1,006 (20%) had albuminuria with albumin excretion ≥ 30mg/g. Among frail participants, prevalences of eGFR cr and eGFR cys <60mL/min/1.73m 2 were 45% and 77%, respectively. Adjusted for covariates, frailty showed a moderate association with eGFR cr and a strong association with eGFR cys and albumin-creatinine ratio. Frail individuals with eGFR cr of 60 to <75mL/min/1.73m 2 were frequently reclassified to lower eGFR categories using eGFR cys (49% to 45-<60, 32% to 30-<45, and 3% to <30mL/min/1.73m 2 ). Hyperpolypharmacy (taking ≥10 classes of medications) was more common in frail individuals (54% vs 38% of nonfrail), including classes requiring kidney clearance (eg, digoxin) and associated with falls and subsequent complications (eg, hypnotic/sedatives and anticoagulants)., Limitations: Cross-sectional study design., Conclusions: Frail individuals had a high prevalence of reduced kidney function, with large discrepancies when reduced kidney function was classified by eGFR cys versus eGFR cr . Given the substantial medication burden and uncertainty in chronic kidney disease classification, confirmation of kidney function with alternative biomarkers may be warranted to ensure careful prescribing practices in this vulnerable population., (Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to evaluate the predictive value of cystatin C (CysC) and estimated glomerular filtration rate (eGFR) regarding vascular lesions and their severity in patients with acute coronary syndrome (ACS)., Methods: According to the results of coronary angiography, 195 ACS patients were divided into a single-vascular-lesion group (91 cases), a dual-vascular-lesion group (67 cases), and a multiple-vascular-lesion group (37 cases) to assess the severity of coronary artery disease according to Gensini scores and to analyze the correlations of CysC and eGFR level with vascular lesions and severity in ACS patients., Results: Intergroup comparisons of univariate and multivariate regression analyses showed that CysC was positively correlated with vascular lesions (P < 0.05), but eGFR showed no correlation. Regarding the severity of vascular lesions, CysC was positively correlated with Gensini score (Pearson's correlation coefficient r = 0.1811, P < 0.05), but eGFR was not correlated (P > 0.05)., Conclusions: Serum CysC levels could reflect the severity of vascular lesions in ACS patients, and a high CysC level had predictive value regarding the severity of vascular lesions in ACS.

It is well known that plasma creatinine concentration is affected by muscle mass, while some studies have suggested cystatin C is affected by body mass index (BMI). The current study was rationalised to assess the effect of BMI on serum cystatin C among elderly CKD patients. Two groups of participants selected for this purpose. Control group consisted for 12 patients whereas 13 patients were selected for study group. Serum Cys C and creatinine was determined by ELIZA and Jaffe Method respectively. Patients were interviewed and necessary information was retrieved. A validated data collection form was developed to record patient demographics and relevant clinical data. Statistical analysis was performed via SPSS version 20. Cystatin C was highest in the obese group (0.77 mg/L; 95% confidence intervals [CI] 0.69-0.77) On multivariate analysis, body fat and GFR (p 0.003) were significant determinants of cystatin C; muscle mass and age affected creatinine significantly (p 0.02). Using cystatin C equation CKD-Epi showed significantly better result in the obese group. Creatinine equation showed significant overestimations of GFR for the study group. Body fat is a significant determinant of cystatin C while creatinine concentration is highly affected by muscle mass and age. Body composition plays an important role in the interpretation of renal function. [ABSTRACT FROM AUTHOR]

Objective: To investigate the relationship between the level of serum cystatin C (s-CC) and reverse-dipper blood pressure (BP) pattern., Design: Cross-sectional study., Setting: Single centre., Participants: A total of 718 hypertensive patients were eventually recruited from cardiac clinics between 2012 and 2014 in the Second Affiliated Hospital, Xi'an Jiaotong University. They were diagnosed as essential hypertension according to their casual office records of systolic blood pressure (SBP) and/or diastolic blood pressure (DBP). Patients were excluded if they were <18 or >90 years old, under antihypertensive treatment, night workers, suffering from acute stroke or myocardial infarction within the past 6 months, diagnosed as secondary hypertension, sleep apnoea or other sleep disorders, renal failure, cardiac failure, chronic obstructive pulmonary disease, women during pregnancy or intolerant to the ambulatory BP monitoring (ABPM)., Measurement: The selected patients were evaluated with 24 hours ABPM. Peripheral venous blood samples were collected to evaluate the s-CC levels by ELISA., Methods: The distribution of hypertensive patients with different levels of s-CC among each circadian BP pattern group was analysed using analysis of variance. Multinomial logistic regression analysis was applied to explore the relationship between the relevant variables and ABPM results., Results: S-CC level in reverse-dipper group (1.19±0.53 mg/L) was increased significantly when compared with dipper group (1.06±0.36 mg/L) (p=0.021). In addition, after multinomial logistic regression analysis, s-CC (OR 1.717; 95% CI 1.033 to 2.854; p=0.037) and diabetes (OR 2.313; 95% CI 1.401 to 3.821; p=0.01) were significantly different between the reverse-dipper group and dipper group. On the other hand, the decline rate of nocturnal SBP (r=-0.117; p=0.002) and DBP (r=-0.089; p=0.018) was negatively correlated with the s-CC level., Conclusions: The s-CC level was significantly higher in the reverse-dipper group than the dipper group and that s-CC was associated with the reverse-dipper pattern of BP examined with 24 hour ABPM., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Background/Aims: Serum creatinine has several drawbacks as marker of glomerular filtration rate (GFR), and therefore serum cystatin C has been proposed as a more optimal GFR marker. Previous reports have suggested benefits of serum cystatin C measurements in patients with renal transplants. The purpose of the present study was to evaluate the diagnostic accuracy of cystatin C measurements compared with enzymatic creatinine measurements as serum markers of GFR (established from plasma clearance of iohexol) in a large cohort of stable renal transplant recipients and in the early postoperative phase. Methods: Renal transplant patients (n = 125) with stable graft function were evaluated from reciprocals of serum creatinine and cystatin C compared with iohexol clearance. Fourteen patients were examined immediately after the onset of renal function. Cystatin C was measured by a particle-enhanced turbidimetric method and creatinine by an enzymatic method. Results: In stable renal transplant recipients, serum cystatin C showed a significantly (p = 0.033) closer correlation (r = 0.89 or 79% co-variance) with iohexol clearance than did serum creatinine (r = 0.81 or 66% co-variance). Using the χ[sup 2] test and a cut-off at 60 ml/min/1.73 m[sup 2] , serum cystatin C levels demonstrated significantly higher sensitivity for early GFR impairment (p = 0.0045) compared with serum creatinine measurements. On the first day after transplantation, serum cystatin C fell more rapidly than serum creatinine. Conclusion: Serum cystatin C levels correlate significantly closer to accurate measurements of GFR and are significantly more sensitive to detect early GFR impairment than enzymatic measurements of creatinine in serum.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The aims of the present study were to evaluate the roles of serum cystatin C (SCysC) and urinary cystatin C (UCysC) in renal function impairment and investigate the optimum cut-off point for renal function impairment among patients with type 2 diabetes mellitus (DM). A total of 742 inpatients and outpatients with type 2 DM (age, 20-75 years) were enrolled in this population-based cross-sectional study. The levels of SCysC and UCysC were determined and the odds ratios (ORs) and 95% confidence interval (CIs) of the calculated risk ratios of the different renal damage indicators were obtained. The levels of UCysC, urinary β2-microglobulin (Uβ2-MG), urinary albumin (UALB) and SCysC in the renal function impairment groups were observed in the following order: GFR-C>GFR-B>GFR-A (P<0.05 or P<0.01). According to the levels of GFR were divided into 4 groups, group GFR-A ≥ 80ml/min, GFR-B group 50-80 ml/min, group Ccr-C 20-50 ml/min, group GFR-D <20 ml/min. Following adjustment for age and gender, multivariate correlation analysis results revealed that levels of Uβ2-MG, UCysC and UALB negatively correlated with the glomerular filtration rate (GFR; P<0.05 or P<0.01). In addition, the duration of DM and the levels of SCysC and serum uric acid were shown to positively correlate with the GFR (P<0.05 or P<0.01). ORs for early renal function impairment significantly increased from the DM duration category of four years (OR, 1.74; 95% CI, 1.54-1.92). Receiver operating characteristic analysis demonstrated that the optimum DM cut-off point was four years, in which 60.79% sensitivity and 69.66% specificity were observed. Therefore, UCsyC levels may be used as an efficient indicator for the evaluation of early renal function impairment among patients with type 2 DM. In addition, renal lesions may initially occur in the renal tubule and then form in the renal glomerulus of patients with type 2 DM.

Background: Accurate renal function measurements are important in the diagnosis and treatment of kidney diseases. In contrast to creatinine, the production of serum cystatin C has been extensively reported to be unaffected by body muscle mass, age, gender, and nutritional status., Methods: Our study included 37 samples from diabetic chronic kidney disease (CKD) patients for whom serum creatinine tests had been requested and 40 samples from a healthy populations in Dong-A University Hospital between May 2010 and June 2010. The assay precision (i.e., the coefficient of variation) and the reference range of the serum cystatin C test were evaluated. We compared the estimated glomerular filtration rates (GFRs) based on cystatin C with those based on creatinine. Moreover, we investigated the influences of age, gender, weight, and muscle mass on serum creatinine and serum cystatin C., Results: There was a positive correlation between GFR based on creatinine and that based on cystatin C (r=0.79, P<0.0001) among the diabetic CKD patients. Serum creatinine and cystatin C were significantly correlated with body weight and muscle mass, but the strengths of these correlations were greater for serum creatinine. The precision study revealed excellent results for both the high and low controls. The 95% reference interval of cystatin C in the healthy population was 0.371 to 1.236 mg/L., Conclusion: Based on these results, we conclude that, despite the strong correlation between serum creatinine and cystatin C, cystatin C is less affected by weight and muscle mass and might represent a better alternative for the assessment of renal function.

Background: Acute kidney injury (AKI) is associated with a high mortality. This study was undertaken to detect the factors associated with the prognosis of AKI., Methods: We retrospectively reviewed 98 patients with AKI treated from March 2008 to August 2009 at this hospital. In these patients, 60 were male and 38 female. Their age ranged from 19 to 89 years (mean 52.4±16.1 years). The excluded patients were those who died within 24 hours after admission to ICU or those who had a history of chronic kidney disease or incomplete data. After 60 days of treatment, the patients were divided into a survival group and a death group. Clinical data including gender, age, history of chronic diseases, the worst laboratory values within 24 hours after diagnosis (values of routine blood tests, blood gas analysis, liver and renal function, levels of serum cystatin C, and blood electrolytes) were analyzed. Acute physiology, chronic health evaluation (APACHE) II scores and 60-day mortality were calculated. Univariate analysis was performed to find variables relevant to prognosis, odds ratio (OR) and 95% confidence interval (CI). Multiple-factor analysis with logistic regression analysis was made to analyze the correlation between risk factors and mortality., Results: The 60-day mortality was 34.7% (34/98). The APACHE II score of the death group was higher than that of the survival group (17.4±4.3 vs. 14.2±4.8, P<0.05). The mortality of the patients with a high level of cystatin C>1.3 mg/L was higher than that of the patients with a low level of cystatin C (<1.3 mg/L) (50% vs. 20%, P<0.05). The univariate analysis indicated that organ failures≥2, oliguria, APACHE II>15 scores, cystatin C>1.3 mg/L, cystatin C>1.3 mg/L+APACHE II>15 scores were the risk factors of AKI. Logistic regression analysis, however, showed that organ failures≥2, oliguria, cystatin C>1.3 mg/L +APACHE II>15 scores were the independent risk factors of AKI., Conclusion: Cystatin C>1.3 mg/L+APACHE II>15 scores is useful in predicting adverse clinical outcomes in patients with AKI.