Different methods for assessing glomerular filtration rate in the elderly

Area of Science:

• Nephrology
• Geriatrics
• Clinical Chemistry

Background:

• Estimating glomerular filtration rate (eGFR) is crucial for managing chronic kidney disease (CKD).
• Cystatin C is a reliable marker for eGFR, but its cost can be a limitation.
• Alternative methods using creatinine are needed for cost-effective eGFR assessment in the elderly.

Purpose of the Study:

• To identify the optimal creatinine-based equation for estimating glomerular filtration rate (eGFR) in elderly individuals.
• To compare the performance of various creatinine-based eGFR equations against cystatin C-based eGFR.

Main Methods:

• A cohort of 166 elderly individuals (≥60 years) was studied.
• Blood samples were analyzed for creatinine and cystatin C.
• eGFR was calculated using Creatinine Clearance, Cockcroft-Gault, MDRD, and CKD-EPI creatinine equations, with CKD-EPI cystatin C as the reference.
• Statistical analysis included linear regression, Bland-Altman plots, and ROC curves.

Main Results:

• The CKD-EPI creatinine equation demonstrated the highest correlation with the reference method.
• Creatinine clearance exhibited the lowest performance.
• Bland-Altman and ROC analyses corroborated the superiority of the CKD-EPI creatinine equation.

Conclusions:

• The CKD-EPI creatinine equation is the preferred method for eGFR estimation in the elderly population.
• The poor performance of creatinine clearance suggests 24-hour urine collection is not required for eGFR assessment in this demographic.
• This finding supports the use of simpler, blood-based markers for routine eGFR monitoring in older adults.