Objective: To investigate the epidemiology and the risk factors of acute kidney injury (AKI) in hospitalized patients in order to help clinicians better understand and prevent AKI.
Methods: All patients hospitalized in Renji Hospital of Shanghai Jiao Tong University, which is a three-level General Hospital in Shanghai, during January to December of 2008 were screened by Lab Administration Network. Study group was comprised of the patients with full clinical data of AKI, as defined by Acute Kidney Injury Network (AKIN). The incidence, etiology and distribution characteristics of hospitalized patients with AKI were retrospectively analyzed. Logistic regression analysis was used to investigate the risk factors in severity of AKI.
Results: Nine hundred and thirty-four patients suffering from AKI for 1 001 episodes were enrolled. The incidence of AKI in hospitalized patients was 2.4% (934/38 734). The ratio of male to female was 1.88:1. The mean age was (60.82 ± 16.94) years old. Higher incidence was seen with an increase in age. Three hundred and thirty-one(35.4%) patients with AKI were found in medical department, 592(63.4%) patients in surgical department and 11(1.2%) patients in department of gynecologic and obstetrics. Analysis of the causes of AKI showed that pre-AKI accounted for 52.0%, followed by renal parenchyma AKI (44.7%) and postrenal AKI (3.3%). The most common reason for AKI was acute tubular necrosis (ATN, 37.5%), followed by absolute (33.6%) and relative inadequacy of blood volume (13.4%). Multivariate logistic regression analysis showed that chronic kidney disease (CKD) [odds ratio (OR)=2.085, 95% confidence interval (95%CI): 1.536-2.830,P<0.01], renal injurious drugs (OR=1.438, 95%CI: 1.087-1.901 ,P<0.05), and failure of organs other than kidney (OR=1.327, 95%CI: 1.014-1.737,P<0.05) were independent risk factors for stage II-III AKI.
Conclusion: AKI is one of the most common clinical syndromes in hospitalized patients. With the increase of age, the incidence increases gradually. The most common reasons for hospitalized AKI are pre-AKI and ATN. CKD, renal injurious drugs and failure of other organs are independent risk factors of medium to serious AKI.