Background: Serum cystatin C has been widely studied as a marker of GFR in adult , is a non-glycosylated, 13.3-kDa protein belonging to cystatin protease inhibitors that produced by all nucleated cells and found in body fluids, including serum. It is catabolized in the proximal renal tubule and is not returned to blood so it is not affected by infections, inflammation , neoplastic malignancy,gender, age, race, protein intake, and muscle mass, unlike serum creatinine. The other previous study is show that congenital cyanotic heart disease patients(CCHD) are frequently have low BMI(Z-score below -2SD), malnutrition, so they may be a delay in diagnosis for Chronic kidney disease (CKD) in this patients because of unreliable serum creatinine in malnutrition patients.This study aim to show prevalence of Chronic kidney disease in congenital cyanotic heart disease by evaluated GFR from serum cystatin C compare with serum creatinine.
Method: A prospective, descriptive study was carried out from November 2019 to October 2020, in patients age 1 years to 18 years with CCHD at Chiangmai University Hospital. Exclusion criterias are acute kidney injury in 3 month , fever with proteinuria , cardiac catherization within 3 months , UD CAKUT, surgery within 3 month, and patients take an enalapril within 1 months before study. Serum cystatin C is evaluated by ELISA kit serum cystatin C and calculated GFR by formular CKiD cystC equation eGFR.
Results: Among 30 patients with CCHD,Male is 14 of 30 (46.7%), female is 16 of 30(53.3%), age 1-7 yr is 66.7%, age 8-13 yr is 30%, age 13-18 is 1%, severe wasted (Z score BMI below -3SD) is 16.7%, wasted(Z-score BMI below -2 SD) is 30%, normal BMI is 53.3%. Albuminuria (urine microalbumin > 30 mg/g) is 16.9%. 7 of 30 (23.3%) is CKD by evaluated GFR from serum creatinine, 14 (46.7%) is CKD by evaluated GFR from serum cystatin C (7 of 14 is CKD from serum creatinine too). A total 14 patients who has CKD from serum cystatin C is BMI z-score below -2SD.
Conclusion: Our study show CCHD who evaluated GFR from serum cystatin C has prevalence of CKD more than evaluated GFR from serum creatinine in patients who has BMI z-score below -2 SD.Albuminuria is not correlate with CKD in this study.So nutrition status, low BMI score can effect GFR from serum creatinine But less effect in GFR from serum cystatin C. this study is limit by low population in this study.
