Baseline characteristics, biochemical variables and medication compared between the five levels of diabetic retinopathy for 267 patients with type 1 diabetes
| All patients* | Diabetic retinopathy at baseline (according to the International Clinical Diabetic Retinopathy Disease Severity Scale) | |||||||
| No apparent DR† | Non-proliferative DR† | Proliferative DR† | ||||||
| Mild | Moderate | Severe | P value‡ | |||||
| n | 267 | 73 | 54 | 63 | 30 | 47 | – | |
| DR (any level) | 194 (73) | – | – | – | – | – | – | |
| Sex | Women | 114 (43) | 33 (45) | 31 (57) | 23 (36) | 10 (33) | 17 (36) | 0.075 |
| Men | 153 (57) | 40 (55) | 23 (43) | 40 (64) | 20 (67) | 30 (64) | ||
| Age (years) | 42 (18–59) | 37 (26–50) | 35 (28–47) | 45 (36–53) | 44 (32–49) | 46 (42–55) | <0.001§ | |
| Diabetes duration (years) | 20 (1–55) | 9 (6–13) | 17 (10–24) | 22 (16–31) | 26 (21–32) | 35 (26–42) | <0.001§ | |
| HbA1c≥53 mmol/mol | 218 (82) | 54 (74) | 38 (70) | 57 (90) | 26 (87) | 43 (92) | 0.002 | |
| MMP-2 (ng/mL) | 154 (66–434) | 146 (119–166) | 143 (122–175) | 162 (137–180) | 152 (129–197) | 164 (135–203) | 0.012§ | |
| High MMP-2 (≥178 ng/mL) | 66 (25) | 10 (14) | 10 (18) | 19 (30) | 10 (33) | 17 (36) | 0.001 | |
| TIMP-2 (ng/mL)¶ | 179 (0.0–468) | 165 (138–195) | 170 (147–188) | 185 (167–212) | 182 (151–209) | 191 (171–220) | <0.001§ | |
| High TIMP-2 (≥205 ng/mL)¶ | 67 (25) | 15 (20) | 6 (11) | 20 (32) | 8 (27) | 18 (38) | 0.008 | |
| Combined high MMP-2 and high TIMP-2 (ng/mL)¶ | 40 (15) | 5 (7) | 3 (6) | 11 (18) | 7 (23) | 14 (30) | < 0.001 | |
| MMP-9 (ng/mL)** | 536 (222–1936) | 552 (419–701) | 536 (394–790) | 535 (435–716) | 566 (417–730) | 497 (401–769) | 0.94§ | |
| MMP-9/NGAL (ng/mL)†† | 21 (3–96) | 24 (15–36) | 24 (14–33) | 20 (15–32) | 22 (11–31) | 18 (10–31) | 0.34§ | |
| MMP-9/TIMP-1 (ng/mL)‡‡ | 15 (1–103) | 15 (8–27) | 14 (8–31) | 16 (11–29) | 17 (8–28) | 14 (8–25) | 0.79§ | |
| MMP-14§§ | 1.5 (0.0–447.0) | 1.8 (0.0–10.1) | 1.6 (0–3.3) | 1.7 (0.0–4.3) | 1.2 (0.0–6.7) | 1.2 (0.0–5.9) | 0.72 | |
| TIMP-3 (ng/mL)¶¶ | 8.2 (1–486) | 9.8 (6.1–13.8) | 7.5 (5.2–14.6) | 7.0 (5.7–10.4) | 7.7 (5.2–10.4) | 8.8 (6.4–10.5) | 0.17§ | |
| Serum creatinine (µmol/L)*** | 70 (28–182) | 70 (62–78) | 68 (58–78) | 70 (61–76) | 70 (62–80) | 72 (64–88) | 0.16§ | |
| Macroalbuminuria††† | 15 (6) | 0 | 0 | 4 (7) | 5 (14) | 7 (16) | <0.001 | |
| Systolic BP>130 mm Hg | 44 (16) | 5 (7) | 5 (9) | 14 (22) | 6 (20) | 14 (30) | <0.001 | |
| Diastolic BP>80 mm Hg | 13 (5) | 3 (4) | 1 (2) | 4 (6) | 3 (10) | 2 (4) | 0.46 | |
| Continuous subcutaneous insulin infusion‡‡‡ | 23 (9)*** | 3 (4) | 2 (4) | 9 (14) | 1 (3) | 8 (17) | 0.018 | |
| Antihypertensive drugs | 89 (33) | 7 (10) | 7 (13) | 27 (43) | 18 (60) | 30 (64) | <0.001 | |
*Data are presented as n (%) or median (min–max).
† Data are presented as n (%) or median (q1, q3).
‡Linear-by-linear association was used unless indicated.
§ Kruskal-Wallis test.
¶Missing value (n): 2.
**Missing value (n): 5.
††Missing value (n): 4.
‡‡Missing value (n): 4.
§§Missing value (n): 9.
¶¶Missing value (n): 6.
***Missing value (n): 13.
†††Missing value (n): 15.
‡‡‡Otherwise multiple daily insulin injections.
BP, blood pressure; DR, diabetic retinopathy; HbA1c, glycated haemoglobin; MMP, matrix metalloproteinase; NGAL, neutrophil gelatinase-associated lipocalin; PDR, proliferative diabetic retinopathy; TIMP, tissue inhibitor of metalloproteinase.