Performance of creatinine-based equations compared in older patients

Area of Science:

• Nephrology
• Geriatric Medicine
• Clinical Chemistry

Background:

• Estimating glomerular filtration rate (GFR) is crucial for assessing kidney function.
• Existing GFR estimation equations lack precision in the elderly population.
• The Berlin Initiative Study (BIS-1) equation was developed to enhance GFR estimation accuracy in older individuals.

Purpose of the Study:

• To compare the accuracy and precision of the BIS-1 equation against the Modification of Diet in Renal Disease (MDRD) Study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations for GFR estimation in older adults.

Main Methods:

• A study involving 224 white patients over 70 years old.
• Simultaneous measurement of plasma creatinine and renal clearance of inulin.
• Comparison of GFR estimation performance using BIS-1, MDRD, and CKD-EPI equations.

Main Results:

• BIS-1 demonstrated superior accuracy, with 75.56% of estimates within ±30% of measured GFR, compared to MDRD (70.67%) and CKD-EPI (72%).
• BIS-1 exhibited the lowest median bias and highest precision and concordance correlation coefficient (CCC).
• For advanced chronic kidney disease (CKD) stages 4 and 5, the CKD-EPI equation showed higher accuracy (P30, bias, CCC) than BIS-1.

Conclusions:

• The BIS-1 equation is the most reliable creatinine-based method for assessing renal function in older white patients, particularly those with CKD stages 1-3.
• CKD-EPI remains a more accurate option for estimating GFR in patients with advanced CKD stages 4 and 5.