Concordance between estimated glomerular filtration rate using equations and that measured using an imaging method.

Area of Science:

• Nephrology
• Nuclear Medicine
• Biomarker Assessment

Background:

• Current guidelines recommend estimating glomerular filtration rate (GFR) using creatinine-based equations (CBE).
• The accuracy of these estimations in clinical practice requires ongoing evaluation.
• Radionuclide imaging offers a direct measurement of GFR.

Purpose of the Study:

• To assess the concordance between GFR measured via radionuclide imaging and estimated by commonly used CBEs.
• To identify potential discrepancies in GFR assessment between different methodologies.

Main Methods:

• GFR was estimated in 421 patients using MDRD-4, CKD-EPI, and Cockcroft Gault equations.
• GFR was measured using 99mTc-DTPA radionuclide imaging.
• Concordance was evaluated using Lin's concordance coefficient and Bland-Altman plots.

Main Results:

• No significant difference was found in average GFR values between the methods.
• A substantial proportion (29%) of participants had a GFR < 60 ml/min/1.73 m2 by CKD-EPI.
• Correlation between CBEs was good, but correlation and concordance with 99mTc-DTPA imaging were low.

Conclusions:

• GFR measurement by 99mTc-DTPA radionuclide imaging demonstrates low correlation and poor concordance with estimations derived from CBEs.
• Clinical reliance on CBEs for GFR assessment may require careful consideration, especially when precise GFR values are critical.