Characteristics of patients with and without gradable fundus photographs at baseline and follow-up
| Characteristics | Patients with gradable photographs (n=1392) | Patients without gradable photographs (n=614) | P value |
| Mean (±SD)/n (%) | Mean (±SD)/n (%) | ||
| Age (years) | 61.2±8.5 | 64.1±9.7 | <0.001 |
| Male, n (%) | 576 (41.4) | 243 (39.6) | 0.45 |
| Income level, n (%) | |||
| Low | 522 (38.4) | 209 (35.7) | 0.41 |
| Moderate | 773 (56.8) | 351 (60.0) | |
| High | 66 (4.9) | 25 (4.3) | |
| Education, n (%) | |||
| Primary or lower | 187 (13.7) | 137 (23.4) | <0.001 |
| Middle/high school | 976 (71.3) | 380 (65.0) | |
| College and above | 206 (15.1) | 68 (11.6) | |
| Current smoker, n (%) | 296 (21.7) | 129 (22.2) | 0.80 |
| Current drinker, n (%) | 321 (23.5) | 99 (17.0) | 0.002 |
| Diabetes treatment, n (%) | |||
| No treatment | 189 (13.9) | 80 (13.8) | 0.97 |
| Oral | 841 (61.8) | 354 (61.3) | |
| Insulin | 332 (24.4) | 144 (24.9) | |
| Proteinuria, n (%) | 440 (31.7) | 227 (37.2) | 0.02 |
| Age of diabetic onset (years) | 53.6±9.7 | 56.2±10.7 | <0.001 |
| Interval between treatment and diagnosis (years) | 1.2±3.1 | 1.2±3.1 | 0.68 |
| Duration of diabetes (years) | 7.6±5.9 | 8.0±6.3 | 0.20 |
| FPG (mmol/L) | 9.2±3.3 | 9.7±3.7 | 0.01 |
| HbA1c (%) | 7.7±2.0 | 7.9±2.2 | 0.07 |
| BMI (kg/m2) | 26.50±3.34 | 26.17±3.64 | 0.053 |
| WHR | 0.97±0.06 | 0.96±0.07 | 0.13 |
| SBP (mm Hg) | 148.2±22.5 | 147.1±25.3 | 0.36 |
| DBP (mm Hg) | 77.5±11.3 | 76.4±11.8 | 0.056 |
| Serum creatinine (μmol/L) | 83.6±18.8 | 88.0±21.2 | <0.001 |
| Blood urea nitrogen (mmol/L) | 6.21±3.42 | 6.35±2.45 | 0.30 |
| Blood uric acid (μmol/L) | 306.9±84.2 | 315.7±94.8 | 0.049 |
| Total cholesterol (mmol/L) | 5.46±1.12 | 5.65±1.50 | 0.005 |
| Total triglycerides (mmol/L) | 2.21±1.68 | 2.18±1.62 | 0.73 |
| LDL (mmol/L) | 3.21±0.89 | 3.32±1.06 | 0.01 |
| HDL (mmol/L) | 1.50±0.37 | 1.45±0.37 | 0.01 |
| CRAE (μm) | 144.8±18.3 | 145.3±30.9 | 0.73 |
| CRVE (μm) | 227.9±28.7 | 221.0±37.0 | <0.001 |
BMI, body mass index; CRAE, central retinal artery equivalent; CRVE, central retinal vein equivalent; DBP, diastolic blood pressure; FPG, fasting plasma glucose; HbA1c, glycosylated haemoglobin A1c; HDL, high-density lipoprotein; LDL, low-density lipoprotein; SBP, systolic blood pressure; WHR, waist:hip ratio.