title: The characteristics and mortality risk factors for acute kidney injury in different age groups in China-a cross sectional study.
abstract: OBJECTIVE
  Age is an independent risk factor for acute kidney injury (AKI). The causes and outcomes of AKI in children, middle-aged, and older patients are different. The objective of this country-based study was to identify the characteristics and mortality factors for AKI in different age groups in China.
  
  
  METHODS
  Using data from 374,286 adult patients (≥18 years) admitted to 44 study hospitals, we investigated the characteristics and mortality risk factors for AKI in four different age groups: 18-39 years of age, 40-59 years of age, 60-79 years of age, and ≥80 years of age. The identification criteria for AKI included the 2012 KDIGO AKI definition and an expanded criterion.
  
  
  RESULTS
  The country-based survey included 7604 AKI patients (7604/374,286, 2.03%). The proportions of AKI in the four age groups were 11.52%, 30.79%, 41.03%, and 16.66%, respectively. In any age group, the patients with AKI stage 1 were the majority (43.4%, 42.4%, 46.4%, and 52.2%, respectively), and the most common classification of AKI was pre-renal AKI (44.3%, 51.3%, 52.3%, and 56.4%, respectively). The higher AKI peak stage occurred for the in-hospital mortality factors for AKI in all age groups; except for the AKI stage 2 patients in the 18-39 age group.
  
  
  CONCLUSIONS
  The characteristics and mortality factors for AKI vary by age in China. Elderly patients were the primary population with AKI, and the most common type of AKI was pre-renal AKI. Special caution should be taken to the old population in hospitalized patients to prevent the pre-renal AKI.
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wei
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Hong
authors.initials: H
authors.lastname: Liu
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Yan-
authors.initials: Y
authors.lastname: Tu
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Ri-Ning
authors.initials: RN
authors.lastname: Tang
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Wang
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Pan
authors.affiliation: a Department of Nephrology, Zhongda Hospital, School of Medicine , Southeast University , Nanjing , China.
authors.forename: Bi-Cheng
authors.initials: BC
authors.lastname: Liu
mesh_terms: D058186:Acute Kidney Injury / Q000401:mortality* / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D002423:Cause of Death / Q000639:trends; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate / Q000502:physiology*; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D055815:Young Adult
keywords: Acute disease; aging; injury; kidney; mortality; renal disease