BackgroundThere is still an ongoing discussion on the prognostic value of cystatin C in assessment of kidney function. Accordingly, the present study aimed to conduct a meta-analysis to provide evidence for the prognostic value of this biomarker for acute kidney injury (AKI) in children.MethodsAn extensive search was performed in electronic databases of Medline, Embase, ISI Web of Science, Cochrane library and Scopus until the end of 2015. Standardized mean difference (SMD) with a 95% of confidence interval (95% CI) and the prognostic performance characteristics of cystatin C in prediction of AKI were assessed. Analyses were stratified based on the sample in which the level of cystatin C was measured (serum vs. urine).ResultsA total of 24 articles were included in the meta-analysis [1948 children (1302 non-AKI children and 645 AKI cases)]. Serum (SMD = 0.96; 95% CI: 0.68-1.24; p < 0.0001) and urine (SMD = 0.54; 95% CI:0.34-0.75; p < 0.0001) levels of cystatin C were significantly higher in children with AKI. Overall area under the curve of serum cystatin C and urine cystatin C in prediction of AKI were 0.83 (95% CI: 0.80-0.86) and 0.85 (95% CI: 0.81-0.88), respectively. The best sensitivity (value = 0.85; 95% CI: 0.78-0.90) and specificity (value = 0.61; 95% CI: 0.48-0.73), were observed for the serum concentration of this protein and in the cut-off points between 0.4-1.0 mg/L.ConclusionThe findings of the present study showed that cystatin C has an acceptable prognostic value for prediction of AKI in children. Since the serum level of cystatin C rises within the first 24 h of admission in patients with AKI, this biomarker can be a suitable alternative for traditional diagnostic measures.

Our results identify that the sensitivity of serum CysC for detecting AKI is higher than that of serum Cr in a heterogeneous pediatric intensive care unit (PICU) population.

To construct reference percentiles for blood pressure (BP) by sex, age and height for the first time in Iran, we used data on 16 972 healthy children, aged 1 month to 18 years, collected during 2000-2010 in Tehran. BP in this population rose steadily with age and height following a very similar trend in both genders up to the age of 14. Systolic BP (SBP) rise was more prominent in younger ages, and after puberty (15-18 years) was greater in boys compared with girls, while the rise in diastolic BP (DBP) was slightly higher in girls. Iranian norms, compared with 'Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents' (US-4th-Report) and the 'German BP Percentiles by Age and Height for Children and Adolescents' (KiGGS), showed a similar pattern of differences for both genders. For example, for Tehrani boys up to 6 years old whose heights were equal to 50th percentile of stature-for-age as well as length-for-age growth charts, the differences in 95th percentile for SBPs compared with the US-4th-report varied from 2-21 mm Hg while compared with KiGGS, maximum of differences was 9 mm Hg. For boys 7-15 years of age, ours were slightly higher than both. For ages of 16 and 17 years, we yielded figures lower than US-4th-report (2 mm Hg) but higher than KiGGS (3 mm Hg). Iranian 95th percentile for DBPs was lower than US-4th-report and KiGGS (1-11 mm Hg). Considering the differences with US-4th-report and KiGSS standards, the references presented in this study should rather be applied in Iranian population.

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