Analysis of occurrence and clinical characteristics of transient and persistent acute kidney injury in hospitalized elderly patients

Abstract

Objective We aimed to study the incidence, clinical characteristics, and risk factors of transient and persistent acute kidney injury (AKI) in very elderly patients. Methods We retrospectively enrolled very elderly patients (aged ≥75 years) from the Geriatric Department of the Chinese PLA General Hospital between January 2007 and December 2015. AKI patients were divided into transient or persistent AKI groups based on their renal function at 3 days post-AKI. Multivariate logistic regression analysis was made for the risk factors associated with persistent AKI in the elderly. Results During the study period, a total of 652 inpatients developed AKI, including 623 males, accounting for 95.6%, with a median age of 87 (84-91) years. Of the 652 patients with AKI, transient AKI occurred in 270 cases (41.4%) and persistent AKI in 382 cases (58.6%). Multivariate logistic regression analysis showed that the Scr peak value (OR=1.020; 95%CI: 1.015-1.026; P<0.001), the increase of blood urea nitrogen (BUN) (OR=1.028; 95%CI: 1.000-1.056; P=0.047), the increase of uric acid (OR=1.002; 95%CI: 1.000-1.003; P=0.040), and the requirement of mechanical ventilation (OR=1.610; 95%CI: 1.012-2.562; P=0.044) were independent risk factors of the persistent AKI in the elderly patients, while the increase of mean arterial pressure (OR=0.985; 95%CI: 0.971-1.000; P=0.043) and elevation of hemoglobin (OR=0.989; 95%CI: 0.980- 0.999; P=0.025) were independent protective factors for persistent AKI in the elderly patients. Conclusions The incidence of transient AKI in the elderly patients was as high as 42%. Increasing the attention of clinicians, and increasing the frequency of monitoring Scr were effective methods to reduce the rate of missed diagnosis for AKI. Early identification of the risk factors might improve the short-term outcomes of patients with AKI. Key words: Acute kidney injury; Transient AKI; Persistent AKI; Elderly people; Risk factors