The Clinical Usefulness of Cystatin C in Evaluating Renal Function in Children with Various Renal Diseases

PURPOSE: GFR(glomerular filtration rate) is a fundamental parameter in detecting renal impairment and predicts the progression of renal disease. Because serum creatinine has several disadvantages, serum cystatin C has been recently proposed as a new endogenous marker for GFR. We compared serum cystatin C with creatinine and creatinine clearance to investigate the clinical usefulness of cystatin C. METHODS: We retrospectively analyzed 46 patients(60 case numbers) who had various renal diseases and classified them into 3 groups according to creatinine clearance(Group 1 : CrCl 60 mL/min/1.73 m2). We measured serum creatinine, cystatin C and creatinine clearance and also analyzed the correlations among them. RESULTS: Serum cystatin C and creatinine showed a similar correlation to creatinine clearance (r=0.685, r=0.640, respectively) and showed similar diagnostic accuracy in detecting decreased GFR(AUC, cystatin C 0.829 vs. creatinine 0.826, P=0.848). Serum cystatin C showed a greater sensitivity for detecting a decreased GFR than creatinine in Group 2 and 3(Group 1 : 100% vs. 100%, Group 2 : 70% vs. 35%, Group 3 : 46% vs. 15%). CONCLUSIONS: Serum cystatin C could be a useful endogenous marker for GFR and would be superior to serum creatinine in early detection of renal impairment in pediatric patients with renal diseases.

Outcome and Prognosis in Critically Ill Children Receiving Continuous Renal Replacement Therapy

PURPOSE: Continuous renal replacement therapy(CRRT) has been the first choice for the treatment of acute renal failure in critically ill children not only in western countries but also in Korea. However, there are very few studies that have analyzed the outcome and prognosis of this modality in Korean children. We performed this study to evaluate the factors associated with the outcome and prognosis of patients treated with CRRT. METHODS: We retrospectively reviewed the medical records of 32 children who had received CRRT at Severance hospital from 2003 to 2006. The mean age was 7.5 years(range 4 days- 16 years) and the mean body weight was 25.8 kg (range 3.2-63 kg). RESULTS: Eleven(34.4%) of the 32 patients survived. Bone marrow transplantation and malignancy were the most common causes of death and underlying disease leading to the need for CRRT. Mean patient weight, age, duration of CRRT, number of organ failures, urine output, estimated glomerular filtration rate(eGFR), C-reactive protein, and blood urea level did not differ significantly between survivors and nonsurvivors. (1) Pediatric risk of mortality(PRISM) III score at CRRT initiation(9.8+/-5.3 vs. 26.7+/-7.6, P<0.0001), (2) maximum pressor number (2.1+/-1.2 vs. 3.0+/-1.0, P=0.038), and (3) the degree of fluid overload(5.2+/-6.0 vs. 15.0+/-8.9, P=0.002) were significantly lower in survivors than in nonsurvivors. Multivariate analysis revealed that fluid overload was the only independent factor reducing survival rate. CONCLUSION: CRRT was successfully applied to the treatment of acute renal failure in a wide range of critically ill children. To improve survival, we suggest the early initiation of CRRT to prevent the systemic worsening and progression of fluid overload in critically ill children with acute renal failure.