Table 1 Characteristics of the patients stratified by RC-level quartiles

n

1647 (≤ 0.35)

1622 (0.36 − 0.58)

1663 (0.59 − 0.90)

1603 (0.91 − 10.89)

6535

T2DM duration ≤ 7 years

856

899

909

911

3575

T2DM duration > 7 years

791

723

754

692

2960

RC (mmol/L)

0.20 (0.10 − 0.30)

0.47 (0.41 − 0.52)

0.72 (0.65 − 0.80)

1.23 (1.03 − 1.61)

0.58 (0.35 − 0.90)

 < 0.001

Age (years)

65 (61 − 70)

64 (60 − 69)

64 (60 − 68)

64 (59 − 68)

64 (60 − 69)

 < 0.001

Male, n (%)

781 (47.4%)

714 (44.0%)

663 (39.9%)

675 (42.1%)

2833 (43.4%)

 < 0.001

T2DM duration (years)

7 (4 − 12)

7 (4 − 11)

7 (4 − 12)

6 (3 − 11)

7 (4 − 11)

 < 0.001

BMI (kg/m²)

24.09 (22.23 − 26.08)

24.22 (22.48 − 26.26)

24.54 (22.94 − 26.84)

24.88 (23.01 − 26.90)

24.44 (22.65 − 26.56)

 < 0.001

FPG (mmol/L)

7.2 (6.3 − 8.3)

7.3 (6.4 − 8.5)

7.3 (6.4 − 8.7)

7.5 (6.5 − 9.0)

7.3 (6.4 − 8.6)

 < 0.001

HbA1c (%)

7.4 (6.5 − 7.8)

7.1 (6.4 − 7.8)

7.2 (6.4 − 7.9)

7.2 (6.6 − 8.0)

7.2 (6.5 − 7.9)

0.028

SBP (mmHg)

130 (124 − 134)

130 (122 − 133)

130 (123 − 134)

130 (122 − 134)

130 (122 − 134)

0.242

DBP (mmHg)

78 (74 − 80)

80 (74 − 82)

78 (74 − 82)

80 (75 − 82)

78 (74 − 82)

 < 0.001

MAP (mmHg)

94.7 (91.7 − 97.3)

95.0 (92.0 − 98.7)

95.0 (92.0 − 98.3)

95.3 (92.0 − 98.7)

95.0 (92.0 − 98.0)

 < 0.001

Hypertension, n (%)

1058 (64.2%)

1018 (62.8%)

1118 (67.2%)

1100 (68.6%)

4294 (65.7%)

0.001

TC (mmol/L)

4.43 (3.81 − 5.06)

4.60 (4.02 − 5.21)

4.90 (4.28 − 5.55)

5.24 (4.58 − 5.99)

4.79 (4.15 − 5.47)

 < 0.001

TG (mmol/L)

1.10 (0.80 − 1.50)

1.10 (0.90 − 1.50)

1.60 (1.40 − 1.90)

2.50 (2.10 − 3.60)

1.50 (1.10 − 2.20)

 < 0.001

HDL-C (mmol/L)

1.40 (1.21 − 1.71)

1.40 (1.18 − 1.65)

1.31 (1.11 − 1.54)

1.14 (0.97 − 1.34)

1.31 (1.10 − 1.57)

 < 0.001

LDL-C (mmol/L)

2.68 (2.08 − 3.33)

2.67 (2.15 − 3.21)

2.81 (2.24 − 3.39)

2.67 (2.09 − 3.30)

2.70 (2.14 − 3.30)

 < 0.001

DR, n (%)

201 (12.2%)

217 (13.4%)

213 (12.8%)

223 (13.9%)

854 (13.1%)

0.508

T2DM duration ≤ 7 years

83 (9.7%)

71 (7.9%)

77 (8.5%)

87 (9.5%)

318 (8.9%)

0.482

T2DM duration > 7 years

118 (14.9%)

146 (20.2%)

136 (18.0%)

136 (19.7%)

536 (18.1%)

0.034

NPDR, n (%)

197 (12.0%)

212 (13.1%)

204 (12.3%)

221 (13.8%)

834 (12.8%)

0.397

PDR, n (%)

4 (0.2%)

5 (0.3%)

9 (0.5%)

2 (0.1%)

20 (0.3%)

0.179

Insulin use, n (%)

151 (9.2%)

157 (9.7%)

156 (9.4%)

127 (7.9%)

591 (9.0%)

0.320

CRAE (μm)

137.77 (127.37 − 147.81)

138.65 (129.33 − 148.54)

138.50 (129.84 − 148.07)

138.71 (129.59 − 149.16)

138.39 (128.99 − 148.49)

0.004

CRVE (μm)

228.49 (211.60 − 244.63)

229.13 (213.62 − 245.51)

231.99 (214.94 − 247.21)

232.28 (215.36 − 250.36)

230.31 (213.82 − 246.84)

 < 0.001

AVR

0.60 (0.56 − 0.65)

0.61 (0.56 − 0.65)

0.60 (0.56 − 0.65)

0.60 (0.56 − 0.65)

0.60 (0.56 − 0.65)

0.037

VT, × 10^–4

9.40 (8.23 − 10.61)

9.36 (8.04 − 10.45)

9.41 (8.24 − 10.51)

9.48 (8.34 − 10.62)

9.41 (8.23 − 10.53)

0.033

D_f

1.48 (1.45 − 1.52)

1.50 (1.46 − 1.52)

1.50 (1.46 − 1.53)

1.50 (1.46 − 1.53)

1.49 (1.46 − 1.53)

 < 0.001