Renal injury in the elderly: diagnosis, biomarkers and prevention

Acute kidney injury (AKI) in the elderly patient is a common iatrogenic complication of major surgery that impacts morbidity, mortality and resource use. Several renal functional and structural changes have been described, including a substantially decreased nephron mass. Loss of renal function defines AKI and is classified by the RIFLE (R: renal risk, I: injury, F: failure, L: Loss and E: End-stage renal disease) criteria; however, it frequently occurs many hours to several days after the injury to the kidney. Therefore, novel biomarkers indicating tubulo-interstitial damage are needed for early AKI diagnosis. The limitations of serum creatinine are much more pronounced in the elderly, including its dependence on muscle mass and the presence of multiple drug use and co-morbidities. Although it is conceivable that earlier AKI diagnosis and application of classical preventive measurements, including postponement of surgery or preference of medical treatment, optimisation of haemodynamics, euvolaemia, aggressive avoidance of nephrotoxic antibiotics or analgesics may translate into better patient outcomes, much more data are needed in this specific cohort.