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Estimation of Nephron Number in Whole Kidney using the Acid Maceration Method
Published on: May 22, 2019
Two novel equations to estimate kidney function in persons aged 70 years or older
Elke S Schaeffner1, Natalie Ebert, Pierre Delanaye
1Charité University Medicine, Campi Virchow, Mitte, Germany. elke.schaeffner@charite.de
Annals of Internal Medicine
|October 3, 2012
Summary
New equations accurately estimate kidney function in older adults. The BIS2 equation, using creatinine and cystatin C, is recommended for individuals 70 and older, with BIS1 as an alternative when cystatin C is unavailable.
Area of Science:
- Nephrology
- Geriatrics
- Biomarkers
Background:
- Current glomerular filtration rate (GFR) estimation equations are not validated in older adults.
- Existing methods may misclassify chronic kidney disease (CKD) staging in the elderly population.
Purpose of the Study:
- To develop and validate the Berlin Initiative Study (BIS) equations for estimating GFR in individuals aged 70 years and older.
- To improve the accuracy of GFR estimation in the geriatric population.
Main Methods:
- A cross-sectional study involving 610 participants aged 70+ years.
- Iohexol plasma clearance was used as the gold standard for measured GFR.
- Developed and validated two novel equations (BIS1: creatinine-based; BIS2: creatinine and cystatin C-based) against existing GFR estimators.
Main Results:
- The BIS2 equation demonstrated the lowest bias and misclassification rate for estimating GFR in older adults.
- Both BIS1 and BIS2 equations confirmed a high prevalence of reduced GFR ( < 60 mL/min/1.73 m²) in the study population.
- BIS2 (11.6%) and BIS1 (17.2%) showed lower misclassification rates compared to other equations.
Conclusions:
- The BIS2 equation is recommended for estimating GFR in individuals aged 70 years and older.
- The BIS1 equation serves as a viable alternative when cystatin C measurements are not accessible.
- Further external validation is needed to confirm the findings.
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