Acute kidney injury in elderly patients: narrative review on incidence, risk factors, and mortality

Abstract

Acute kidney injury (AKI) is characterized by a sudden renal dysfunction with consequent increase of nitrogenous products, hydroelectrolytic and acid–base disorders. Its prevalence is high in hospitalized populations (4.9%–7.2%), especially in intensive care units (ICUs). Despite all the technical and therapeutic advances that have occurred in the last few decades, the overall mortality of AKI patients remains high, reaching 80% in ICU patients. Several conditions predispose a patient to progress with AKI, including age, sepsis, surgeries, and comorbidities, such as systemic arterial hypertension, diabetes mellitus, heart disease, neoplasia, and chronic renal disease. Among these risk factors, age is emphasized, since, due to advances in the health area, there has been an increase in life expectancy, hence an increase in the demand of the elderly population for health services. At the same time, the elderly present a greater predisposition to the development of AKI, either due to kidney senility, or because of the high prevalence of comorbidities present, and medical interventions such as the use of contrasts and medications, which can also trigger AKI. Considering the relevance of the social role of the elderly and the scarcity of studies on AKI in the elderly admitted to the ICU, further studies are needed. This review article was elaborated considering the purpose: to assess incidence, risk factors, and mortality of AKI in elderly patients admitted to ICUs. Published studies were collected using the following inclusion criteria: be accessible in online databases (Lilacs, Scielo, and PubMed), have been published since 2000 and written in English, Portuguese, or Spanish. The descriptors used for the survey were “Acute Kidney Injury”, “Aging”, and “Elderly”. All items that did not fit in the above inclusion criteria were discarded. We have also presented a synthesis of the knowledge acquired during this review.

Acute kidney injury following on-pump or off-pump coronary artery bypass grafting in elderly patients: a retrospective propensity score matching analysis

“…AKI has been associated with progression to chronic kidney disease(CKD) and dialysis in many reports [28] . CKD and dialysis might exert negative efferts on the long-term survival inevitably especially in elderly patients [29] . Unfortunately, there are no pharmacologic agents known to reduce the risk of AKI or treat established AKI.…”

Impact of Kidney Donor Profile Index Scores on Post-Transplant Clinical Outcomes Between Elderly and Young Recipients, A Multicenter Cohort Study

“…In contrast, allograft functions within a year after KT were the lowest in the high KDPI-young KTR subgroup. Baseline capacity to recover may be lower in kidneys with high KDPI score than kidneys with low KDPI score because of the underlying chronic change as we mentioned above 20 . However, the metabolic demands may be higher in young-KTRs than elderly-KTRs.…”

Clinical Characteristics and Factors Affecting Mortality in Elderly Patients Admitted to Respiratory Intensive Care Unit

“…We suggest that these may have originated from impairment of renal function and its related effect on blood gases with advanced age. It has been shown in the medical literature that renal functions and blood gas parameters were affected in elderly patients (22). The association of hypoalbuminemia with mortality has been shown before (23).…”