Objective To compare the clinical characteristics of community-acquired acute kidney injury (CA-AKI) and hospital-acquired acute kidney injury (HA-AKI) patients.Methods Hospital network system was employed to screen the clinical data of adult patients in the First Affiliated Hospital in Xinjiang Medical University in January to July 2013.A total of 19 528 patients were screened,and 544 AKI patients were identified based on KIDGO (Kidney Disease:Improving Global Outcomes) AKI guidelines.Three hundred and thirty patients were included in HA-AKI group and 214 patients in CA-AKI group.Clinical variables including mortality were analyzed retrospectively.Results The incidence of AKI in hospitalized patients was 2.8％ (544/19 528):1.7％ in CA-AKI group and 1.1％ in HA-AKI group.The mean age in CA-AKI group was significantly older than that in HA-AKI group [(62.9 ± 16.8) years vs (56.6± 15.9) years].Medical patients in CA-AKI group accounted for 62.4％,and surgical patients in HA-AKI group accounted for 64.1％.The co-morbid diseases were cardiac disease,hypertension,diabetes and chronic liver disease.Majority of AKI was caused by pre-renal etiologies.The length of hospitalization was significantly shorter in CA-AKI group compared to that in HA-AKI group [12(8,20) days vs 19 (12,27) days,P ＜ 0.01].Compared to that in HA-AKI group,all-cause mortality was significantly lower in CA-AKI group (11.5％ vs 20.1％,P=0.005).Results by multivariate logistic regression analysis demonstrated that the common independent risk factors of AKI in both groups were ICU hospitalization and shock.The independent risk factor of AKI in CA-AKI group was diabetes (OR=3.019).In contrary,the independent risk factors of AKI in HA-AKI group were elderly (≥65 years) (OR=3.303),oliguria (24 h urine volume ＜ 400 ml) (OR=6.906),use of antiinflammatory drugs (OR=13.079) and multiple organ dysfunction syndrome (OR=17.778).Conclusions The incidence of AKI in hospitalized patients is not rare,among which both communityacquired and hospital-acquired AKI are mainly caused by pre-renal etiologies.All-cause mortality is lower in community-acquired AKI compared to that in hospital-acquired AKI and the independent risk factors are different between CA-AKI and HA-AKI.