Pediatric reference values for serum creatinine and estimated glomerular filtration rate in Iranians: Tehran Lipid and Glucose Study

Reference serum creatinine levels according to sex, age, and height in children with Down syndrome

Standard serum creatinine (S-Cr) levels in healthy children fluctuate with age and sex. However, it is unclear if this fluctuation in S-Cr levels is present for children with Down syndrome (DS) who show atypical growth rate. Therefore, we aimed to establish specific reference S-Cr levels for DS and compare them with the prevailing standard levels. We retrospectively reviewed 984 children with DS aged 3 months to 18 years who visited our medical center. Patients with diseases affecting S-Cr levels were excluded. We calculated the reference S-Cr levels according to sex, age, and length/height using medical records. A total of 3765 examinations of 568 children with DS were registered for this study. Ages and S-Cr levels were examined for boys (y = 0.032x + 0.20; r = 0.868, P < 0.0001), and girls (y = 0.024x + 0.23; r = 0.835, P < 0.0001). S-Cr levels in children aged >9 years were significantly higher in boys than in girls. The 430 children with DS aged 2-8 years were examined 1867 times. Height and S-Cr levels showed a significantly strong positive correlation (r = 0.670, P < 0.001) with regression equation y = 0.37x. The quintic equations calculated with S-Cr levels and length/height for boys (336 children, 2043 tests, r = 0.887) and girls (232 children, 1722 tests, r = 0.805) werey =  - 6.132x⁵ + 32.78x⁴ - 67.86x³ + 68.31x² - 33.14x + 6.41, and y = 0.09542x⁵ + 1.295x⁴ - 6.401x³ + 10.35x² - 6.746x + 1.772. All calculated results varied from the standard levels for healthy children.Conclusion: This study established reference S-Cr levels and quintic equations specific for children with DS. These reference levels would be potentially useful in evaluating S-Cr levels and renal function in this population. What is Known: •Standard serum creatinine levels vary with age and sex to reflect muscle mass. •Reference serum creatinine levels specific to children with Down syndrome who show growth rates different from those of healthy children have not been established. What is New: •Serum creatinine levels in children with Down syndrome showed different trajectories for sex, age, and length/height when compared with the standard levels for healthy children. •This report on specific reference serum creatinine levels for children with Down syndrome is useful in the assessment of renal function in these children.

Predictors of early adulthood hypertension during adolescence: a population-based cohort study

Background

Some longitudinal studies have shown that blood pressure tracks from adolescence to adulthood, yet there is limited evidence regarding the predictive factors of adulthood hypertension during adolescence. This study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS) to investigate the role of some factors in adolescence, measured in the first examination (1999–2001), to predict adulthood hypertension in the 4th examination (2009–2011).

Methods

Overall, 1579 subjects, aged 10–19 years, were used for the analysis of the current study. Mean age (SD) of participants at the baseline was 14.2 (2.5) years and 55% of them were female. A forward stepwise approach (p-value <0.2 for enter and >0.05 for removal) was considered to keep significant covariates among common variables including gender, body mass index, waist circumference, wrist and hip circumferences, fasting blood sugar, triglycerides, high density lipoprotein cholesterol, total cholesterol (TC), systolic (SBP) and diastolic blood pressure (DBP). Variance inflation factor (VIF) showed some multicollinearity for anthropometric variables (VIFs between 3.5 and 10). Multivariable logistic regression revealed that gender, blood pressure, wrist circumference and total cholesterol in adolescents are important predictors for adulthood hypertension.

Results

The risk increased by 4% and 39% per each 10 mmHg and 1 mmol/L increase in SBP/DBP and TC, respectively; additionally, females had a 70% lower risk. Among anthropometric variables, wrist circumference remained in the model, with 50% per centimeter increase in the risk of hypertension.

Conclusions

Wrist circumferences and TC had significant roles in predicting hypertension through adolescence to adulthood.

Electronic supplementary material

The online version of this article (10.1186/s12889-017-4922-3) contains supplementary material, which is available to authorized users.

Acute kidney injury in patients with Kawasaki disease

BACKGROUND

Kawasaki disease was well known for coronary artery abnormalities with few reports of incidence of acute kidney injury (AKI). Our aim was to identify the rate of AKI in patients with Kawasaki disease and its associated factors.

METHODS

All patients with Kawasaki disease admitted to a medical center from February 2004 to August 2014 were evaluated. Data collection included serum creatinine level, serial echocardiography reports, white blood cell count, C-reactive protein level, alanine transaminase level, urine white blood cell count, and renal ultrasound reports if available. AKI was defined when a patient's serum creatinine level was higher than 1.5 times upper limits of age-specific serum creatinine levels.

RESULTS

This cohort study included 332 patients (191 boys and 141 girls; aged 0.12 to 11.3 y, median 1.39 y) and 93 patients (28%) of them had AKI. Multivariate logistic regression revealed that age and alanine transaminase level were significantly associated with AKI (odds ratio (OR): 0.521, 95% confidence interval (CI): 0.377-0.718, P < 0.001, and OR: 1.003, 95% CI: 1.000-1.005, P = 0.017, respectively).

CONCLUSION

This study demonstrated that AKI exists in substantial proportion of patients with KD. Young age and high alanine transaminase level are the main associated factors for AKI in these patients.