Table 1.
Basic characteristics of the included studies
| First author | Year | Country | Study design | Data source | Follow-up (y) | Sample size | Type of DM | Male (%) | Age at baseline (y) | Diagnosis of DR |
|---|---|---|---|---|---|---|---|---|---|---|
| Sabanayagam [11] | 2019 | Singapore | Prospective cohort study | Population-based | Median 8.8 | 2964 | T2DM: 98.2% | 50.6 | 40–80 | Fundus photography |
| Takao [12] | 2020 | Japan | Retrospective cohort study | Hospital-based | Median 18.6 | 1902 | T2DM | 80.3 | Mean 55.6 | Ophthalmoscope FFA |
| Kim [13] | 2002 | Korea | Prospective cohort study | Hospital-based | 2 | 365 | T2DM | NA | NA | Ophthalmoscope |
| Rajala [14] | 2000 | Finland | Prospective cohort study | Hospital-based | 4 | 428 | T2DM: majority | 31.8 | 27–88 | Fundus photography |
| Hsieh [15] | 2017 | China | Retrospective cohort study | Hospital-based | Median 6.6 | 761 | T2DM | 56.4 | Mean 63.6 | Ophthalmoscope FFA |
| Juutilainen [16] | 2007 | Finland | Prospective cohort study | Population-based | 18 | 824 | T2DM | 51.6 | 45–64 | Ophthalmoscope |
| Liew [17] | 2008 | Australia | Prospective cohort study | Population-based | 12 | 199 | T2DM | NA | NA | Fundus photography |
| Lövestam-Adrian [18] | 2006 | Sweden | Prospective cohort study | Hospital-based | 10 | 363 | T2DM | 64.5 | Mean 54.1 | Fundus photography |
| Mottl [19] | 2014 | United States | Prospective cohort study | Hospital-based | Mean 5 | 3210 | T2DM | 61.8 | Mean 61.3 | Fundus photography |
| Ono [20] | 2002 | Japan | Retrospective cohort study | Hospital-based | Median 11.6 | 223 | T2DM | 77.1 | Mean 60.3 | Fundus photography FFA |
DM: diabetes mellitus, DR: diabetic retinopathy, FFA: fundus fluorescein angiography, NA: not available