Objectives: The aim of this study was to explore the prognostic impact of clinical factors on the short-term outcomes of renal function (RF) in very elderly patients with acute kidney injury (AKI).
Patients and methods: We carried out a retrospective cohort study of only very elderly patients who developed AKI at the geriatric department of a tertiary medical center during the period 2007–2015. All patients with AKI were followed up for 90 days after AKI diagnosis or until death. Survivors were divided into recovery and nonrecovery groups according to their RF 90 days post-AKI. RF recovery was defined as an estimated glomerular filtration rate (eGFR) of ≥60 mL/min/1.73 m².
Results: In total, 668 patients (39.0%) developed AKI, and 652 patients were included in the final analysis. The median age of this population was 87 years, with 95.6% being male. The 90-day mortality rate was 33.6%. Of the 433 survivors, 316 (73.0%) recovered to their baseline eGFR. Body mass index (BMI), baseline eGFR, low mean aortic pressure (MAP), low prealbumin level, hypoalbuminemia, oliguria, blood urea nitrogen (BUN) level, and more severe AKI stage were independent risk factors associated with nonrenal recovery or death. AKI etiology, evaluated by peak serum creatinine (SCr) level and the requirement for dialysis, was not associated with nonrenal recovery.
Conclusion: Risk factors for the poor outcomes of RF in very elderly patients with AKI were BMI, baseline eGFR, low MAP, low prealbumin level, hypoalbuminemia, oliguria, BUN level, and more severe AKI stage. Identifying risk factors may help to improve patient outcomes.
Keywords: acute kidney injury, elderly, prognosis, renal function, risk factors