Modification of the Schwartz equations for children increases their accuracy at eGFR > 60 mL/min/1.73 m(2).

AIM: Estimation of eGFR in children with normal kidney function using the Schwartz equations results in underestimating real GFR. MATERIALS AND METHODS: We propose modification of three Schwartz equations - two based on creatinine concentration (eGFRScrBS bedside) and (eGFRScr) and one 3-marker based on creatinine, urea and cystatin C concentrations (eGFRS3M). The iohexol test (reference method) was performed 417 times in 353 children >2 years with mean GFR: 98 ± 31.6 ml/min/1.73m(2). The assessment included also the Filler and Zappitelli equations. The modification was performed using methods: (1) based on equation, eGFRcor = a [eGFR - T] + T, where T = 50, if eGFR > T, and a equals for: eGFRScrBS 1.4043, for eGFRScr 2.0048, for eGFRS3M 1.2951, and (2) based on correction of all coefficients of the original equation. RESULTS: For comparison of all the results and for children with GFR< 60, 60-90, 90-135 and > 135 ml/min/1.73m(2) the correlation coefficient, relative error (RE) and root mean square relative error (RMSRE) was employed and revealed improvement of RE from 25.9 to 6.8 and 3.9% (depending on the correction method) for eGFRScr; from 19 to 8.1 and 3.9% for eGFRScrBS and: from 11.6% to 2.0 and 2.3% for eGFRS3M (respectively). The RMSRE values changed from 30 to 21.3 and 19.8% for eGFRScr, from 25.1 to 21.6 and 19.8% for eGFRScrBS and from 19.1 to 15.8 and 15.3 % for eGFRS3M. CONCLUSIONS: Modifications of Schwartz equations at GFR > 60 ml/min/1.73m(2) significantly improves the accuracy of calculating eGFR. The 3-markers equation is more accurate and should be employed frequently.

Which equations should and which should not be employed in calculating eGFR in children?

PURPOSE: We assessed the reliability of calculating eGFR in children as compared to the iohexol disappearance test (GFR-I), which was performed 417 times in 353 children aged 2 and more. MATERIAL/METHODS: eGFR was estimated with equations based on serum creatinine: Schwartz (1: eGFR-Scr), Cockroft-Gault (2: eGFR-CG) and MDRD (3: eGFR-MDRD), and on creatinine clearance (4: eGFR-U), or relying on serum cystatin C: Hoeck (5: eGFR-H), Bokenkamp (6: eGFR-B) and Filler (7: eGFR-F), and on the three Schwartz markers (8: eGFR-S3M). Mean relative error (RE), correlation (R), Bland-Altman analysis and accuracy of GFR-I were studied in all patients and in subgroups: at GFR<60ml/min/1.73m(2); in children aged ≤12 and >12. RESULTS: The results by eGFR-Scr, eGFR-S3M demonstrated no statistical difference to GFR-I at GFR<60ml/min/1.73m(2), but underestimated eGFR at higher filtration values by 11.6±15.1% and 19.1±16.4, respectively (p<0.0000). The eGFR-B, eGFR-F and eGFR-MDRD equations illustrated important overestimation of reference GFR results (RE: 84±44.2%; 29.5±27.9%, 35.6±62%; p<0.0000 for all). The MDRD and C-G formulas showed statistically better consistency in children aged >12. A good agreement was achieved by the eGFR-H equation (5.1±21.9%; p<0.0000; R=0.78). CONCLUSIONS: (1) Schwartz equations show a good conformity at GFR<60ml/min/1.73m(2), but underestimate the results at higher GFR values. (2) The Bokenkamp equation with original coefficient should not be employed in children. (3) The use of the Hoeck formula in all children and C-G and MDRD formula in children aged >12 is possible. (4) The error of eGFR calculations increases at higher GFR values.

[Mycophenolate mofetil in treatment of childhood nephrotic syndrome--preliminary report]. / Mykofenolan mofetilu w leczeniu dzieci z zespolem nerczycowym--doniesienie wstepne.

The management of nephrotic syndrome (NS) in children remains a clinical challenge for pediatricians and pediatric nephrologists. Especially, the treatment of patients with steroid-resistant (SR) and steroid-dependent (SD) nephrotic syndrome, because they are at risk for developing complications from prolonged exposure to steroids, CsA and alkylating agents. Mycophenolate mofetil (MMF) is a selective and reversible inhibitor of inosine monophosphate dehydrogenase used above all in transplantology and recently also in patients with nephrotic syndrome. The aim of this study was to tentatively assess the usefulness and the safety of MMF as an immunosuppressive agent in children with steroid-resistant NS, in whom remission was not obtained with previous treatment regimens, and those with steroid-dependent NS, in whom severe adverse reactions were observed in steroid and cyclosporine therapy. The study included 19 children with NS (11 girls, 8 boys) aged 7 to 19.5 years (a mean of 13.5), treated at the Deptartment of Pediatric Nephrology. The duration of disease was from 1 to 16 years (a mean of 9.3). The patients were divided into 3 groups: I--9 children with steroid-dependent NS; II--6 children with steroid-dependent NS and episodes of steroid-resistance; III--4 children with steroid-resistant NS. All patients in groups II and III required multi-drug therapy (prednisone, cyclosporine A, methylprednisolone, chlorambucil, cyclophosphamide) before MMF was introduced. MMF was administered orally: 180-600 mg/m2 body surface/dose, twice daily. The follow-up period lasted for 4 to 16 months (a mean of 7.7). The clinical outcome analysis included decrease or disappearance of proteinuria, clinical improvement and/or possibility of tapering therapy intensity, especially the dosage of steroids and/or CsA. Also, renal function was monitored with serum cystatine C concentration. Particular attention was paid to adverse effects of MMF upon the gastro- intestinal tract and/or opportunistic infections. All medication (apart from MMF) could be discontinued in 4 patients; in 15 cases, prednizone dose was reduced and in 9 cases CsA dose was reduced or discontinued. In group I (SD) steroid treatment could be reduced from a mean prednisone dose of 22.8 to 3.6 mg/m2/48 hours (p=0.018), in groups II and III, in spite of 50 % reduction of a mean prednisone dose, the difference did not reach statistical significance. During MMF therapy Csa treatment could be reduced from a mean CsA dose 4.3 to 2.9 mg/kg/24 hours (p=0.008). Improvement or preservation of stable renal function was observed in all patients--cystatin C levels decreased significantly from a mean 1.35 to 0.96 mg/l (p=0.007). Adverse reaction to MMF (abdominal pain) was observed in 2 patients (nausea, vomiting, diarrhoea in 1, CMV infection in 1). The initial clinical observation of MMF treatment in nephrotic patients shows its best effect in the group of patients with steroid-dependent NS. MMF can safely be used in children with NS. The introduction of MMF allows for reduction of other chronically used medications, especially CsA and steroids.