title: World incidence of AKI: a meta-analysis.
abstract: OBJECTIVE
  The burden of AKI around the globe has not been systematically examined.
  
  
  METHODS
  A systematic review (2004-2012) of large cohort studies was conducted to estimate the world incidence of AKI and its stages of severity and associated mortality, and to describe geographic variations according to countries, regions, and their economies. AKI definitions were reclassified according to the Kidney Disease Improving Global Outcomes (KDIGO) staging system. Random-effects model meta-analyses and meta-regressions were used to generate summary estimates and explore sources of heterogeneity.
  
  
  RESULTS
  There were 312 studies identified (n=49,147,878) , primarily in hospital settings. Most studies originated from North America, Northern Europe, and Eastern Asia, from high-income countries, and from nations that spent ≥5% of the gross domestic product on total health expenditure. Among the 154 studies (n=3,585,911) that adopted a KDIGO-equivalent AKI definition, the pooled incidence rates of AKI were 21.6% in adults (95% confidence interval [95% CI], 19.3 to 24.1) and 33.7% in children (95% CI, 26.9 to 41.3). The pooled AKI-associated mortality rates were 23.9% in adults (95% CI, 22.1 to 25.7) and 13.8% in children (95% CI, 8.8 to 21.0). The AKI-associated mortality rate declined over time, and was inversely related to income of countries and percentage of gross domestic product spent on total health expenditure.
  
  
  CONCLUSIONS
  Using the KDIGO definition, 1 in 5 adults and 1 in 3 children worldwide experience AKI during a hospital episode of care. This analysis provides a platform to raise awareness of AKI with the public, government officials, and health care professionals.
authors.affiliation: Kidney and Dialysis Research Laboratory, Division of Nephrology, Department of Medicine, St. Elizabeth's Medical Center, Boston, Massachusetts, USA.
authors.forename: Paweena
authors.initials: P
authors.lastname: Susantitaphong
authors.forename: Dinna N
authors.initials: DN
authors.lastname: Cruz
authors.forename: Jorge
authors.initials: J
authors.lastname: Cerda
authors.forename: Maher
authors.initials: M
authors.lastname: Abulfaraj
authors.forename: Fahad
authors.initials: F
authors.lastname: Alqahtani
authors.forename: Ioannis
authors.initials: I
authors.lastname: Koulouridis
authors.forename: Bertrand L
authors.initials: BL
authors.lastname: Jaber
mesh_terms: D058186:Acute Kidney Injury / Q000191:economics / Q000453:epidemiology* / Q000401:mortality; D000328:Adult; D000352:Africa, Northern / Q000453:epidemiology; D000354:Africa, Western / Q000453:epidemiology; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D002648:Child; D019049:Developed Countries / Q000191:economics; D003906:Developing Countries / Q000191:economics; D005060:Europe / Q000453:epidemiology; D014943:Global Health; D005102:Health Expenditures; D006801:Humans; D015994:Incidence; D009520:New Zealand / Q000453:epidemiology; D009656:North America / Q000453:epidemiology; D012720:Severity of Illness Index; D013020:South America / Q000453:epidemiology