Comparing GFR Estimating Equations Using Cystatin C and Creatinine in Elderly Individuals

Area of Science:

• Nephrology
• Geriatric Medicine
• Biomarker Research

Background:

• Current guidelines recommend CKD-EPI equations for eGFR reporting.
• The combination of creatinine and cystatin C (eGFRcr-cys) is suggested for enhanced accuracy.
• Optimal filtration markers and equations for elderly populations remain under investigation.

Purpose of the Study:

• To compare the performance of various eGFR equations in elderly individuals.
• To evaluate the accuracy of combined creatinine and cystatin C markers against single markers.
• To determine the preferred eGFR reporting method for community-dwelling elderly populations.

Main Methods:

• Study included 805 adults from the AGES-Reykjavik Study (mean age 80.3 years).
• Measured GFR (mGFR) using plasma clearance of iohexol.
• Assessed eGFR using CKD-EPI, Japanese, BIS, and CAPA equations with creatinine and cystatin C.
• Evaluated equations based on bias, precision, and accuracy.

Main Results:

• CKD-EPI equations demonstrated comparable or superior performance against Japanese, BIS, and CAPA equations.
• eGFRcr-cys showed better performance than eGFRcr and eGFRcys individually across multiple metrics.
• Prevalence of decreased GFR was 39% in this elderly cohort.

Conclusions:

• CKD-EPI equations are suitable for eGFR estimation in community-dwelling elderly individuals.
• Combining creatinine and cystatin C provides a more accurate eGFR assessment in this demographic.
• The findings support the use of eGFRcr-cys with CKD-EPI equations for elderly patients.