Age, Gender, and Race Effects on Cystatin C Levels in US Adolescents
ABSTRACT The objective of this study was to describe the normal range of serum cystatin C and identify factors associated with variability in serum cystatin C contrasting with factors that are known to influence creatinine levels in the general US adolescent population.
Serum cystatin C and creatinine were measured in 719 participants aged 12 to 19 yr in the Third National Health and Nutrition Examination Survey, a national cross-sectional survey conducted in 1988 through 1994. We calculated gender- and race/ethnicity-specific cystatin C and creatinine ranges and conducted multivariable linear regression analyses to assess factors that contribute to variability in cystatin C and creatinine levels.
Overall, the mean serum cystatin C level was 0.84 mg/L and was higher in male than female individuals and higher in non-Hispanic white versus non-Hispanic black and Mexican American individuals. The mean serum creatinine was 0.71 mg/dl and was higher in male than in female individuals but lower in non-Hispanic white and Mexican American compared with non-Hispanic black individuals. Unlike creatinine, which increases with age from 12 to 19 yr, cystatin C levels decrease, particularly in female individuals. After adjustment for age, gender, and race/ethnicity, uric acid and blood urea nitrogen were significantly associated with cystatin C levels.
Serum cystatin C is significantly related to gender, age, race/ethnicity, uric acid, and blood urea nitrogen in adolescents.
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ABSTRACT: Individuals with reduced glomerular filtration rate (GFR) are at greater risk for cardiovascular disease and other comorbidities. Creatinine-based equations are used to estimate GFR, identify patients with potential kidney disease, and classify them into different stages since serum creatinine is insensitive to changes in the GFR. The aim of our work was to evaluate diagnostic performance of serum cystatin C and neutrophil gelatinase-associated lipocalin (NGAL) as markers of kidney function in patients with reduced GFR. Fifty cases at different stages of renal impairment and 30 healthy control subjects were tested. Only serum NGAL and cystatin C were higher in stage 2 chronic kidney disease (CKD) when compared to the control group (p < 0.05). For stages 3–5 the median levels of cystatin C, NGAL, and creatinine were found to be significantly higher than the control group. ROC curve constructed to differentiate stage 2 patients from the controls showed AUC for NGAL 0.795, sensitivity 86%, and specificity 63.3%; AUC for cystatin C 0.957, sensitivity 86%, and specificity 90%; and AUC for creatinine 0.738. Frequency of cases that tested positive for NGAL and cystatin C in stage 2 was higher than those in control group (p < 0.05) with an OR of 10.364 (95% CI 1.099–97.686) for NGAL and OR 54 (95% CI 4.7–613) for cystatin C. NGAL and cystatin C exhibited higher sensitivity than creatinine for diagnosis of stage 2 CKD. Their use as adjunctive diagnostic tools in patients with mildly reduced GFR may be justified on the long term to diagnose early renal insult.Comparative Clinical Pathology 05/2012; 22(3). DOI:10.1007/s00580-011-1404-3
- Clinical Biochemistry 09/2011; 44(13):S7–S8. DOI:10.1016/j.clinbiochem.2011.08.023 · 2.28 Impact Factor
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ABSTRACT: Serum cystatin C has emerged as a new and potentially more reliable marker of kidney function. However, its utility and performance in patients with acute kidney injury (AKI), particularly for the prediction of dialysis requirement, is not well known. Prospective cohort study. Adult patients with AKI enrolled at 2 academic medical centers, at time of nephrology consultation. Serum cystatin C (primary predictor), serum creatinine, and serum urea nitrogen levels and 24-hour urine output measured at enrollment. The composite of dialysis requirement or in-hospital death. COVARIATES: Acute Physiology and Chronic Health Evaluation II (APACHE II) score, liver disease, sepsis, and mechanical ventilation. 200 participants were enrolled for this analysis. Mean age was 65 years, 55% were men, and mean APACHE II score was 20. In unadjusted analyses, increases in serum cystatin C (odds ratio [OR], 1.87; 95% confidence interval [CI], 1.36 to 2.59), serum creatinine (OR, 1.53; 95% CI, 1.12 to 2.09), and serum urea nitrogen levels (OR, 1.84; 95% CI, 1.34 to 2.54) were associated with a higher odds (per 1-SD increase) for the composite outcome, whereas greater urine output (OR, 0.56; 95% CI, 0.39 to 0.80) was associated with lower odds. These associations persisted after adjustment for APACHE II score. The addition of serum cystatin C, serum creatinine, and serum urea nitrogen levels or urine output to a basic model entailing APACHE II score, liver disease, sepsis, and assisted mechanical ventilation improved its prediction, evidenced by increases in areas under a receiver operator characteristic curve from 0.816 to 0.829, 0.826, 0.837, and 0.836, respectively. However, there was no significant difference between each of these models. Observational study, single serum cystatin C measurement. In patients with AKI, serum cystatin C level performs similarly to serum creatinine level, serum urea nitrogen level, and urine output for predicting dialysis requirement or in-hospital death. Larger studies are needed to confirm these findings.American Journal of Kidney Diseases 08/2009; 54(6):1025-33. DOI:10.1053/j.ajkd.2009.05.022 · 5.76 Impact Factor