Table 1. Characteristics of the included studies.
| First author | [R] | Year | Country | Ethnicity | Sample size |
Source | DT | Comparisons (n) | AJR | NOS |
|---|---|---|---|---|---|---|---|---|---|---|
| Ran | [28] | 2010 | China | Asian | 50 | Plasma | 2 | CN/NO* (18) MI (17) MA (15) | Yes | 7 |
| Fujita | [29] | 2006 | Japan | Asian | 53 | Serum | 2 | CN (20) NO (19) MI (18) | Yes | 6 |
| Kato | [30] | 2008 | Japan | Asian | 198 | Serum | 2 | NO (116) MI (47) MA (24) | Yes | 4 |
| Komaba | [31] | 2006 | Japan | Asian | 179 | Serum | 2 | NO (86) MI (44) MA (23) | Yes | 5 |
| Koshimura | [32] | 2004 | Japan | Asian | 38 | Serum | 2 | NO (18) MI (7) MA (13) | Yes | 7 |
| Saito | [33] | 2007 | Japan | Asian | 280 | Serum | 2 | CN (49) MA (22) | Yes | 6 |
| Jorsal | [34] | 2013 | Denmark | Western | 145 | Serum | 1 | CN (55) NO (58) MI (43) MA (44) | No | 5 |
| Schalkwijk | [35] | 2006 | Europe | Western | 543 | Serum | 1 | NO (328) MI (82) MA (128) | No | 5 |
| Panduru | [36] | 2015 | Finland | Western | 2,090 | Serum | 1 | CN (111) NO (1451) MI 319) MA (320) | No | 7 |
| Saraheimo | [37] | 2008 | Finland | Western | 1,330 | Serum | 1 | CN (204) NO (818) MI (216) MA (296) | No | 6 |
| Saraheimo | [38] | 2005 | Finland | Western | 189 | Serum | 1 | NO (66) MI (63) MA (60) | No | 7 |
| Hadjadj | [39] | 2005 | France | Western | 126 | Plasma | 1 | MI (18) MA (108) | No | 8 |
| Yilmaz | [40] | 2008 | Turkey | Western | 411 | Serum | 2 | CN (38) MI (40) MA (45) | Yes | 8 |
[R] Reference number; DT: diabetes type; n: number of studies (n = 13); CN: control; NO: normoalbuminuria; MI: microalbuminuria; MA: macroalbuminuria; CN/NO*: NO is CN; AJR: Rodriguez et al. meta-analysis (yes and no indicate that the article was either in AJR or not, respectively); NOS: Newcastle-Ottawa Scale