Table 1. Key characteristics of included studies.
| Author | Country of study | Year of publication | Target Condition | Sample analysed (N) | Diagnosis Criteria used | Blood glucose Test | Prevalence* (%) of diabetes with reference standard | No. (n) of diabetes diagnosed with reference standard | Prevalence of prediabetes based on reference standard | No. of prediabetes based on reference standard |
|---|---|---|---|---|---|---|---|---|---|---|
| Little [51] | USA | 1988 | Diabetes | 381 | WHO | HbA1c | 34 | 112 | - | - |
| Husseini [52] | Norway | 2000 | Diabetes | 445 | WHO | FCBG | 2.7 | 12 | - | - |
| Rodriguez-Moran [53] | Mexico | 2001 | Diabetes | 712 | ADA | FPG | 9.12 | 65 | - | - |
| Daniel [54] | Australia | 2002 | Diabetes | 3249 | ADA & WHO | FPG | 11.6 | 377 | - | - |
| Mannucci [45] | Italy | 2003 | Diabetes | 1215 | WHO | FPG | 80 | - | - | |
| Nakagami [55] | Multi-country | 2002 | Diabetes | 17512 | - | FPG | 6 | 1051 | - | - |
| Al Lawati [56] | Oman | 2007 | Diabetes | 4917 | ADA & WHO | FPG | 9.9 | 489 | - | - |
| Somnnavar [57] | India | 2009 | Diabetes | 1333 | WHO & ADA | RCBG | 13.9 | 185 | - | - |
| Zhou [40] | China | 2010 | Diabetes & prediabetes | 903 | WHO | HbA1c | 11.1 | 100 | 22.4 | 202 |
| Araneta [58] | Japan | 2010 | Diabetes | 933 | ADA | HbA1c | 15.5 | 145 | - | - |
| Kramer [59] | Brazil | 2010 | Diabetes | 2107 | ADA | HbA1c | 198 | - | - | |
| Mohan V [22] | India | 2010 | Diabetes | 2188 | WHO | HbA1c | 10.1 | 220 | - | - |
| van’t Riet [60] | Netherlands | 2010 | Diabetes | 2753 | WHO | HbA1c | 4 | 107 | - | - |
| Choi [61] | Korea | 2011 | Diabetes | 9375 | ADA | HbA1c | 6.8 | 635 | - | - |
| Bhowmik [41] | Bangladesh | 2013 | Diabetes & prediabetes | 2293 | WHO | HbA1c | 7.9 | 181 | 8.6 | 197 |
| Zhao [62] | China | 2013 | Diabetes & prediabetes | 993 | WHO | FCG | 5.7 | 57 | 14.6 | 145 |
| Wu [63] | China | 2013 | Diabetes & prediabetes | 3354 | WHO | HbA1c | 21.26 | 725 | 40.16 | 1347 |
| Ma Hui [64] | China | 2013 | Diabetes & prediabetes | 1973 | WHO | HbA1c | 13.7 | 271 | 24 | 474 |
| Huang [43] | China | 2013 | Diabetes | 6540 | ADA | HbA1c | 6.04 | 422 | - | - |
| Vlaar [65] | Netherlands | 2013 | Diabetes & prediabetes | 944 | ADA | HbA1c | 3.7 | 35 | 20.2 | 191 |
| Liang [66] | China | 2014 | Diabetes & prediabetes | 8239 | WHO | HbA1c | 10.7 | 880 | 19 | 1565 |
| Huang [67] | USA | 2015 | Diabetes | 5782 | ADA | FPG | - | 231 | - | - |
| Aekaplakorn [68] | Thailand | 2015 | Diabetes & prediabetes | 6884 | ADA | FPG | - | 759 | - | |
| Zemlin [69] | South Africa | 2015 | Prediabetes | 667 | ADA | HbA1c | - | - | 27.7 | 185 |
| Bao [70] | China | 2015 | Diabetes & prediabetes | 7464 | WHO & ADA | FPG | - | 282 | 9 | - |
| Incani [71] | Italy | 2015 | Diabetes & prediabetes | 462 | ADA | HbA1c | 11 | 51 | 65 | 300 |
| Aviles Santa [72] | USA | 2016 | Diabetes | 15507 | ADA | HbA1c | 4.4 | 764 | - | - |
| Hird [42] | South Africa | 2016 | Diabetes | 1077 | WHO | HbA1c | 3.5 | 38 | - | - |
| Karnchanasorn [73] | USA | 2016 | Diabetes | 5764 | ADA | HbA1c | 6.8 | 392 | - | - |
| Liu [74] | China | 2016 | Diabetes & prediabetes | 7611 | WHO | HbA1c | - | 411 | - | 473 |
| Zou [75] | China | 2016 | Diabetes | 3050 | WHO | HbA1c | 10.2 | 311 | - | - |
| Herath [76] | Sri Lanka | 2017 | Diabetes | 254 | ADA & WHO | HbA1c | 16.1 | 41 | - | - |
| Wu [77] | China | 2017 | Diabetes | 4325 | WHO | HbA1c | 13.8 | - | - | |
| Zhou [78] | China | 2018 | Diabetes & prediabetes | 7909 | WHO | HbA1c | 8.79 | 695 | 19.1 | 1514 |
| Lim [79] | Singapore | 2018 | Diabetes | 3540 | ADA | HbA1c & FPG | - | 332 | - | - |
| Prakashchandra [80] | South Africa | 2018 | Diabetes | 1378 | ADA | HbA1c & FPG | - | 154 | - | - |
| Katulanda [81] | Sri Lanka | 2019 | Diabetes | 4014 | ADA | FPG | 4.7 | 191 | - | - |
* Prevalence or number of participants with diabetes based on OGTT/2hrPG values.