Renal Functional Reserve and Renal Recovery After Acute Kidney Injury

The baseline glomerular filtration rate (GFR) and renal functional reserve (RFR), which denotes the kidney’s ability to increase GFR in response to certain stimuli, are critical factors in determining patients’ susceptibility to kidney damage. When GFR is within normal limits and RFR is intact, even repeated and intense potentially nephrotoxic exposures may result in subclinical kidney damage. Conversely, impaired GFR or loss of RFR can lead to acute kidney injury (AKI) even with mild exposure. Following an episode of AKI, GFR may return to baseline (clinical renal recovery) despite the loss of RFR. In such cases, patients become more vulnerable to subsequent kidney damage and other adverse events. A comprehensive definition of full renal recovery, which incorporates biomarkers of kidney damage and RFR, remains unknown and necessitates further investigation.