Albuminuria: all you need to predict outcomes in chronic kidney disease?

Abstract

Screening for chronic kidney disease frequently starts with assessment of estimated glomerular filtration rate (eGFR). In current approaches, further evaluation will only include measurement of albuminuria in case of eGFR less than 60 ml/min/1.73 m. We will review whether this screening approach is correct. Albuminuria is an important predictor of both cardiovascular and kidney outcomes in chronic kidney disease. The predictive value of albuminuria for these endpoints is not only independent of well known risk factors, including diabetes and hypertension, but it is also independent of eGFR. Many individuals with normal eGFR have albuminuria. More research is needed to define why albuminuria adds to eGFR in predicting outcomes. After leakage through the glomerular filter, albumin is not only excreted in urine, but also reabsorbed by tubules. Albuminuria may, therefore, be a marker of both glomerular and tubular damage, whereas eGFR is merely a marker of glomerular damage. As many individuals with an eGFR more than 60 ml/min/1.73 m have microalbuminuria, and albuminuria is an independent predictor of both renal and cardiovascular outcomes, screening for chronic kidney disease should at least include measurement of albuminuria. Future studies should consider whether the inclusion of (other) markers of tubular damage will further improve our ability to predict outcomes in patients with chronic kidney disease.