# A Systematic Review Comparing the Prognostic Role of eGFR According to CKD-EPI and Older Age Validated Equations in Older Adults

## TL;DR

This study compared how well different formulas for estimating kidney function predict health outcomes in older adults, finding no major differences in predicting mortality.

## Contribution

The study is the first to systematically compare the prognostic value of CKD-EPI and older age-validated eGFR equations in older adults.

## Key findings

- No evidence that CKD-EPI or older age-validated eGFR equations differ in predicting mortality in older adults.
- Cystatin C-based equations showed stronger associations with mortality than creatinine-based equations.
- Limited data on hospitalizations, cardiovascular outcomes, and kidney failure prediction using these equations.

## Abstract

Assessing the clinical relevance of reduced estimated glomerular filtration rate (eGFR) in older adults is challenging because GFR naturally declines with age and not all equations, including the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, have been validated for use in older adults. This systematic review compared the association between eGFR and health outcomes in older adults using eGFR equations validated for older age and the CKD-EPI eGFR.

Prognostic factor systematic review and meta-analysis.

Community-dwelling adults aged ≥ 65 years.

Studies using CKD-EPI and at least one of Berlin Initiative Study 1, Berlin Initiative Study 2, European Kidney Function Consortium, Full Age Spectrum, and Revised Lund-Malmo equations to calculate eGFR in association with mortality, cardiovascular outcomes, hospitalizations, or kidney failure. This study was registered on PROSPERO (ID: CRD42022359839).

Meta-analysis was undertaken using random-effects models.

Thirteen studies met inclusion criteria with a total of 102,893 participants. The pooled mean age was 80 years (IQR: 76-84), and baseline CKD-EPI2009 eGFR was 63 mL/min/1.73m2 (IQR: 55-71). The overall quality of data was low, and most studies did not adjust for albuminuria. There was insufficient data assessing the outcomes of cardiovascular outcomes, hospitalizations, or kidney failure. There was no evidence that the association between eGFR and mortality varied according to whether an older age validated equation or CKD-EPI was used. Reduced eGFR according to cystatin C equations had stronger associations with mortality than creatinine-based equations.

Limited number of studies and overall low quality of data.

There was no evidence that the association between eGFR and mortality in older adults differed between CKD-EPI and eGFR equations validated for older age. Studies comparing eGFR equations as predictors of hospitalizations, cardiovascular outcomes, or kidney failure were lacking.

Assessing the clinical relevance of reduced estimated glomerular filtration rate (eGFR) in older adults is challenging, as GFR naturally declines with age, and not all estimating equations, including the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, have been validated for use in older adults. We undertook a systematic review of studies that compared the association between eGFR and health outcomes in older adults using CKD-EPI and older age validated equations, such as the Berlin Initiative Study equations. There was no evidence that the association between eGFR and mortality differed according to whether an older age validated eGFR equation or CKD-EPI was used; however, the quality of the available data was low.