Table 1.

Characteristics of the 154 studies that used a KDIGO-equivalent AKI definition

All StudiesStudies of AdultsStudies of Children
No. of studies15413024
Sample size22,220 (95–1,126,636)26,240 (509–1,126,636)593 (95–3396)
Percentage of male participants63 (28–100)65 (28–100)56 (49–79)
Age of participants (yr)51.6 (0.0–80.3)a60.6 (25.5–80.3)4.7 (0.0–11.4)a
Studies by clinical setting
 Community acquired7 (5)6 (5)1 (4)
 Critical care41 (27)32 (25)9 (38)
 Cardiac surgery42 (27)35 (27)7 (29)
 Trauma4 (2)4 (3)0 (0)
 Heart failure1 (1)1 (1)0 (0)
 Hematology/oncology3 (2)3 (2)0 (0)
 Nephrotoxins4 (2)2 (1)2 (8)
 Hospital acquired, unspecified52 (34)47 (36)5 (21)
Studies by continent
 Australia and New Zealand9 (6)9 (7)0 (0)
 Asia21 (14)18 (14)3 (13)
 Europe51 (33)45 (35)6 (25)
 America70 (45)55 (42)15 (62)
 Africa0 (0)0 (0)0 (0)
 Multiple continents3 (2)3 (2)0 (0)
Studies by world zoneb
 Australia and New Zealand9 (6)9 (7)0 (0)
 Eastern Asia17 (11)15 (12)2 (8)
 Western Asia2 (1)1 (1)1 (4)
 Southern Asia2 (1)2 (2)0 (0)
 South East Asia0 (0)0 (0)0 (0)
 Eastern Europe2 (1)1 (1)1 (4)
 Western Europe15 (10)13 (10)2 (8)
 Northern Europe12 (8)10 (8)2 (8)
 Southern Europe18 (11)17 (13)1 (4)
 Multi-zone Europe4 (3)4 (3)0 (0)
 North America64 (42)50 (38)14 (60)
 South America6 (4)5 (3)1 (4)
 North Africa0 (0)0 (0)0 (0)
 Western Africa0 (0)0 (0)0 (0)
 Multiple zones3 (2)3 (2)0 (0)
Studies by latitude
 North138 (89)115 (88)23 (96)
 South15 (10)14 (11)1 (4)
 North and South1 (1)1 (1)0 (0)
Country income classificationc
 Low income1 (1)1 (1)0 (0)
 Lower middle income1 (1)1 (1)0 (0)
 Upper middle income20 (13)16 (12)4 (17)
 High income130 (84)110 (85)20 (83)
 Not available2 (1)2 (1)0 (0)
Country total health expenditure (% of GDP)d
 <58 (5)7 (5)1 (4)
 5–1068 (45)58 (45)10 (42)
 >1076 (49)63 (48)13 (54)
 Not available2 (1)2 (2)0 (0)
  • Data are presented as the mean (range) or n (%). KDIGO, Kidney Disease Improving Global Outcomes; GDP, gross domestic product.

  • a A zero value indicates newborns.

  • b According to the United Nations geo-scheme classification (11).

  • c According to the World Bank's classification of income of countries (12).

  • d According to the World Health Organization (14).