Glomerular filtration rate determination by creatinine and cystatin-C in patients with acute pyelonephritis

Background: measurement of glomerular filtration rate (gfr) and monitoring of it in any patient on nephrotoxic drugs is very important. recently, cystatin c (cys-c) has been introduced as a better marker for determining and monitoring renal function than creatinine especially in a mild decrease of gfr. this study was done to assess the change of gfr measurement based on serum cys-c and creatinine and their comparison in children with acute pyelonephritis on amikacin. methods: all children with acute pyelonephritis who were admitted in nephrology ward were enrolled in this study. serum creatinine, serum cys-c and the gfr calculation based on them were measured in patients on the day of admission (day zero) and then on days 3 and 7 after the start of treatment with amikacin and p-value less than 0.05 was considered significant.results: among the 70 children, 61 patients were females and the others were males. mean age was 42.66±41.53 months. estimated gfr based on creatinine on day 0 (before amikacin administration), 3 and 7 were 72.41±20.89 ml/min/1.73 m², 78.42±21.15 ml/min/1.73 m² and 80.5±22.43 ml/min/1.73 m², respectively. moreover, gfr based on cys-c during these days were 116.23±58.9 ml/min/1.73 m², 116.49±53.31 ml/min/1.73 m² and 108.37±51.02 ml/min/1.73 m², respectively (p<0.05). conclusions: according to this study, decrease of gfr calculation based on cys-c was seen and estimated gfr was not changed according to creatinine. so, we recommend the use of cys-c for the monitoring of renal function in any patient treated with nephrotoxic drugs such as amikacin.