Cystatin C is not a better estimator of GFR than plasma creatinine in the general population

Abstract

Accurate measurement of glomerular filtration rate (GFR) is complicated and costly; therefore, GFR is commonly estimated by assessing creatinine or cystatin C concentrations. Because estimates based on cystatin C predict cardiovascular disease better than creatinine, these estimates have been hypothesized to be superior to those based on creatinine, when the GFR is near the normal range. To test this, we measured GFR by iohexol clearance in a representative sample of middle-aged (50-62 years) individuals in the general population, excluding those with coronary heart or kidney disease, stroke or diabetes mellitus. Bias, precision (median and interquartile range of estimated minus measured GFR (mGFR)), and accuracy (percentage of estimates within 30% of mGFR) of published cystatin C and creatinine-based GFR equations were compared in a total of 1621 patients. The cystatin C-based equation with the highest accuracy (94%) had a bias of 3.5 and precision of 18 ml/min per 1.73 m², whereas the most accurate (95%) creatinine-based equation had a bias of 2.9 and precision of 15 ml/min per 1.73 m² The best equation, based on both cystatin C and creatinine, had a bias of 7.6 ml/min per 1.73 m², precision of 15 ml/min per 1.73 m², and accuracy of 92%. Thus, estimates of GFR based on cystatin C were not superior to those based on creatinine in the general population. Hence, the better prediction of cardiovascular disease by cystatin C than creatinine measurements, found by others, may be due to factors other than GFR.

Prediabetes and Risk of Glomerular Hyperfiltration and Albuminuria in the General Nondiabetic Population: A Prospective Cohort Study

“…19 The RENIS-T6 included a representative sample of 1627 persons aged 50-62 years from the general population without self-reported kidney disease, myocardial infarction, stroke or diabetes. A description of the study participants and enrollment in the RENIS-T6 is shown in Figure 1 and has been previously published in detail.…”

“…A description of the study participants and enrollment in the RENIS-T6 is shown in Figure 1 and has been previously published in detail. 19 The RENIS Follow-Up Study (RENIS-FU) was conducted from September 2013 to January 2015. Seven persons had a possible adverse reaction to iohexol in the RENIS-T6, and 23…”

GFR Normalized to Total Body Water Allows Comparisons across Genders and Body Sizes

“…Further details about the iohexol analysis and the method for calculating GFR have been described previously. 32 Plasma-creatinine analyses were performed on the Hitachi modular model with an enzymatic method that has been standardized against isotope dilution mass spectroscopy (CREA Plus; Roche Diagnostics, GmbH, Mannheim, Germany). Estimated GFR was calculated as ml/min per 1.…”

Sistatin C: böbrek işlevleri azalmakta olan çocuklarda glomerüler filtrasyon hızı ölçümünde daha yararlı bir değişken olabilir mi?

“…While there are studies reporting that cystatin C may be a good indicator in determining GFR, other studies have reported that it has no superiority over creatinine (19,(21)(22)(23)(24)(25)(26)(27)(28). Therefore, cystatin C is being used for monitoring renal function in clinical practice, though it has not replaced creatinine in use (23,24).…”