Comparison of estimated creatinine clearance, estimated GFR from creatinine and cystatin C as a parameter of renal function, and analysis of factors for the difference among these parameters

Abstract

As an index of renal function in patients, the concentration of serum cystatin C (CysC) is known to be superior to serum creatinine. Recently, the estimated glomerular filtration rate calculated from CysC (eGFRcys) has been more frequently used than that calculated from serum creatinine (eGFRcreat) or than the estimated creatinine clearance (CCr). However, few reports have compared these parameters in many patients. The present study compares eGFRcys vs eGFRcreat and eGFRcys vs CCr in 1,163 in-patients of Hokkaido Gastroenterology Hospital, to clarify the reasons for the differences among these parameters and to specify the factor that most influences evaluation of renal function. The average eGFRcreat and average CCr of the 1,163 patients was found to be roughly the same, but eGFRcys was found to be higher than those parameters; the mean of difference between eGFRcyc and eGFRcreat, and that between eGFRcys and CCr was 27.6 and 21.4, respectively. To divide patients whose difference between eGFRcys and eGFRcreat or CCr was larger or smaller than the mean (27.6, 21.4), we used multiple logistic regression analysis to assess which factor most affects the renal function of patients. A significant correlation was found between [eGFRcys - CCr] and serum albumin level. Moreover, correlations were found between [eGFRcys - eGFRcreat] and gender, body mass index and serum albumin. These data suggest that the value of eGFRcreat and CCr were lower than eGFRcys, and that it changed enough to affect the renal function values. The factor influenãng this difference would not be muscle mass, but rather nutritional status.