Epidemiology and Clinical Correlates of AKI in Chinese Hospitalized Adults

Abstract

Background and objectives: Comprehensive epidemiologic data on AKI are particularly lacking in Asian countries. This study sought to assess the epidemiology and clinical correlates of AKI among hospitalized adults in China.

Design, setting, participants, & measurements: This was a multicenter retrospective cohort study of 659,945 hospitalized adults from a wide range of clinical settings in nine regional central hospitals across China in 2013. AKI was defined and staged according to Kidney Disease Improving Global Outcomes criteria. The incidence of AKI in the cohort was estimated using a novel two-step approach with adjustment for the frequency of serum creatinine tests and other potential confounders. Risk factor profiles for hospital-acquired (HA) and community-acquired (CA) AKI were examined. The in-hospital outcomes of AKI, including mortality, renal recovery, length of stay, and daily cost, were assessed.

Results: The incidence of CA-AKI and HA-AKI was 2.5% and 9.1%, respectively, giving rise to an overall incidence of 11.6%. Although the risk profiles for CA-AKI and HA-AKI differed, preexisting CKD was a major risk factor for both, contributing to 20% of risk in CA-AKI and 12% of risk in HA-AKI. About 40% of AKI cases were possibly drug-related and 16% may have been induced by Chinese traditional medicines or remedies. The in-hospital mortality of AKI was 8.8%. The risk of in-hospital death was higher among patients with more severe AKI. Preexisting CKD and need for intensive care unit admission were associated with higher death risk in patients at any stage of AKI. Transiency of AKI did not modify the risk of in-hospital death. AKI was associated with longer length of stay and higher daily costs, even after adjustment for confounders.

Conclusion: AKI is common in hospitalized adults in China and is associated with significantly higher in-hospital mortality and resource utilization.

Keywords: acute renal failure; epidemiology and outcomes; hospitalization.

Figure 1.

Flow chart of the study population selection. SCr, serum creatinine.

Figure 2.

Incidence of AKI in various clinical settings. The number of patients with a clinical setting is indicated by n. The dotted vertical line specifies the overall incidence of AKI in the analysis set. For clinical procedures during hospitalization, only hospital-acquired AKI (HA-AKI) was counted. CA-AKI, community-acquired AKI.

Figure 3.

Kaplan–Meier plot of cumulative rates of in-hospital death by AKI stage. Gray zones indicate the 95% confidence intervals of the corresponding estimates.

Figure 4.

The hazard ratios of in-hospital death among patients at different stages of AKI in three special settings. The settings are in the presence or absence of preexisting CKD (A), intensive care (B), and transient hospital-acquired AKI (C). S1–S3 in the labels denotes AKI stages 1–3, respectively. Dots and lines indicate the hazard ratio (HR) estimates and the corresponding 95% confidence intervals, respectively. All HRs were calculated using non-AKI without indicated setting as the reference and adjusted for age, sex, comorbidities, and clinical procedures. ICU, intensive care unit.