Acute Kidney Injury in Elderly Persons

Steven G. Coca, DO, MS

Disclosures

Am J Kidney Dis. 2010;56(1):122-131. 

In This Article

Risk Factors for AKI in Elderly Individuals

The higher incidence of AKI in elderly persons potentially can be attributed to the following factors: (1) comorbid conditions that accumulate with age may facilitate AKI (eg, renovascular disease and congestive heart failure); (2) comorbid conditions may necessitate procedures, drugs, or surgery that function as kidney stressors and nephrotoxins; and (3) the kidney undergoes age-dependent structural and functional alterations over time (Box 1).[9–22] The result of the latter is decreased glomerular filtration rate (GFR) at baseline and diminished kidney reserve in the setting of pathophysiologic challenges, making elderly patients very vulnerable to acute stress and more likely to develop clinically relevant AKI.

Few studies in the published literature thoroughly attribute cause to AKI. Few studies discriminate between acute tubular necrosis and prerenal AKI effectively enough to draw meaningful conclusions about the true proportions of these kidney "syndromes," although some studies have estimated that 40% of AKI in the elderly is caused by acute tubular necrosis, and 30%, by prerenal causes.[23,24] Approximately one-quarter of AKI in elderly patients is caused by obstruction.[7,24] Elderly individuals also are more likely to have chronic kidney disease (CKD), congestive heart failure, hypertension, renovascular disease, and diabetes and to undergo surgery (especially cardiac and vascular surgery). Commensurate with these conditions and risks, elderly patients are more likely to be exposed to nephrotoxic contrast (during cardiac or vascular arteriography), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and nonsteroidal anti-inflammatory agents for osteoarthritis. The latter 2 classes of agents (angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and nonsteroidal anti-inflammatory agents) modulate kidney autoregulation and increase the risk of hemodynamically mediated AKI. Thus, the combination of changes in the aging kidney, abnormalities in other organ systems, and exposure to various pharmaceutical agents makes elderly individuals most susceptible for the development of AKI.

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