Table 1.
Baseline clinical features of study participants by HbA1c categories.
| Variables | C1 | C2 | C3 | C4 | p-Value |
|---|---|---|---|---|---|
| N (%) | 3645 (23.3) | 5081 (32.5) | 3608 (23.0) | 3322 (21.2) | |
| Deaths, n (%) | 737 (20.2) | 1049 (20.6) | 858 (23.8) | 958 (28.8) | <0.001 |
| Age, years | 65.6 ± 10.6 | 67.1 ± 9.9 | 67.1 ± 10.2 | 66.3 ± 10.8 | <0.001 |
| Male gender, n (%) | 2233 (57.1) | 2903 (55.9) | 2018 (52.6) | 1748 (56.9) | <0.001 |
| Smoking, n (%) | <0.001 | ||||
| Never | 2021 (55.4) | 2850 (56.1) | 2090 (57.9) | 1888 (56.8) | |
| Former | 1107 (30.4) | 1472 (29.0) | 960 (26.6) | 868 (26.1) | |
| Current | 517 (14.2) | 759 (14.9) | 558 (15.5) | 566 (17.0) | |
| Diabetes duration, years | 9.0 ± 8.9 | 12.5 ± 9.9 | 15.7 ± 10.1 | 16.1 ± 10.2 | <0.001 |
| HbA1c, % | 5.93 ± 0.46 | 6.97 ± 0.29 | 7.93 ± 0.28 | 9.77 ± 1.31 | <0.001 |
| (mmol·mol−1) | (41.3 ± 5.0) | (52.7 ± 3.2) | (63.2 ± 3.1) | (83.3 ± 14.3) | |
| BMI, kg·m−2 | 28.6 ± 4.9 | 28.6 ± 4.9 | 29.1 ± 5.2 | 29.7 ± 5.5 | <0.001 |
| Waist circumference, cm | 101.8 ± 10.0 | 101.9 ± 10.0 | 102.7 ± 10.6 | 104.0 ± 11.1 | <0.001 |
| Triglycerides, mmol·L−1 | 1.46 ± 0.94 | 1.49 ± 0.85 | 1.56 ± 0.89 | 1.84 ± 1.27 | <0.001 |
| Total cholesterol, mmol L−1 | 4.74 ± 0.96 | 4.77 ± 0.95 | 4.75 ± 0.96 | 4.89 ± 1.09 | <0.001 |
| HDL cholesterol, mmol·L−1 | 1.31 ± 0.36 | 1.31 ± 0.35 | 1.28 ± 0.34 | 1.24 ± 0.35 | <0.001 |
| LDL cholesterol, mmol L−1 | 3.43 ± 0.92 | 3.46 ± 0.91 | 3.47 ± 0.92 | 3.65 ± 1.05 | 0.01 |
| Non-HDL cholesterol, mmol L−1 | 2.78 ± 0.84 | 2.79 ± 0.83 | 2.76 ± 0.82 | 2.83 ± 0.90 | <0.001 |
| Systolic BP, mmHg | 136.3 ± 17.5 | 137.9 ± 17.7 | 139.6 ± 18.2 | 138.6 ± 18.7 | <0.001 |
| Diastolic BP, mmHg | 79.0 ± 9.4 | 78.6 ± 9.2 | 78.9 ± 9.5 | 78.7 ± 9.7 | 0.16 |
| Pulse pressure, mmHg | 57.3 ± 15.3 | 59.3 ± 15.6 | 60.8 ± 16.0 | 60.0 ± 15.8 | <0.001 |
| Anti-hyperglycaemic treatment, n (%) | |||||
| Lifestyle | 1017 (27.9) | 762 (15.0) | 192 (5.3) | 142 (4.3) | <0.001 |
| Insulin | 440 (12.1) | 913 (18.0) | 1062 (29.4) | 1509 (45.4) | <0.001 |
| Non-insulin agents | 2188 (60.0) | 3406 (67.0) | 2354 (65.2) | 1671 (50.3) | <0.001 |
| Metformin | 1746 (47.9) | 2840 (55.9) | 2206 (61.1) | 1853 (55.8) | <0.001 |
| Pioglitazone | 87 (2.4) | 167 (3.3) | 163 (4.5) | 137 (4.1) | <0.001 |
| Acarbose | 36 (1.0) | 43 (0.8) | 47 (1.3) | 44 (1.3) | 0.09 |
| Sulfonylureas | 820 (22.5) | 1677 (33.0) | 1472 (40.8) | 1281 (38.6) | <0.001 |
| Repaglinide | 335 (9.2) | 537 (10.6) | 371 (10.3) | 282 (8.5) | 0.01 |
| Agents causing hypoglycaemia, n (%) | 1538 (42.2) | 2944 (57.9) | 2646 (73.3) | 2702 (81.3) | <0.001 |
| Lipid-lowering treatment, n (%) | 1572 (43.1) | 2389 (47.0) | 1728 (47.9) | 1549 (46.6) | <0.001 |
| Anti-hypertensive treatment, n (%) | 2509 (68.8) | 3611 (71.1) | 2601 (72.1) | 2351 (70.8) | <0.001 |
| Albuminuria, mg·day−1 | 53.8 ± 225.5 | 68.7 ± 373.2 | 74.4 ± 329.7 | 96.0 ± 293.1 | <0.001 |
| Serum creatinine, μmol·L−1 | 81.3 ± 38.0 | 80.4 ± 35.4 | 80.4 ± 31.8 | 82.2 ± 31.8 | 0.27 |
| eGFR, mL·min−1·1.73 m−2 | 81.6 ± 21.0 | 80.3 ± 20.1 | 79.9 ± 20.5 | 79.2 ± 22.6 | <0.001 |
| DKD phenotype, n (%) | <0.001 | ||||
| No DKD | 2554 (70.1) | 3385 (66.6) | 2269 (62.9) | 1776 (53.5) | |
| Albuminuric DKD with preserved eGFR | 532 (14.6) | 877 (17.3) | 691 (19.2) | 866 (26.1) | |
| Non-albuminuric DKD | 321 (8.8) | 465 (9.2) | 360 (10.0) | 330 (9.9) | |
| Albuminuric DKD with reduced eGFR | 238 (6.5) | 354 (7.0) | 288 (8.0) | 350 (10.5) | |
| DR, n (%) | <0.001 | ||||
| No DR | 3178 (87.2) | 4185 (82.4) | 2658 (73.7) | 2168 (63.5) | |
| Non-advanced DR | 242 (6.6) | 503 (9.9) | 586 (16.2) | 616 (18.5) | |
| Advanced DR | 225 (6.2) | 393 (7.7) | 364 (10.1) | 538 (16.2) | |
| CVD, n (%) | |||||
| Any | 699 (19.2) | 1086 (21.4) | 906 (25.1) | 929 (28.0) | <0.001 |
| Myocardial infarction | 354 (9.7) | 514 (10.1) | 445 (12.3) | 429 (12.9) | <0.001 |
| Coronary revascularization | 295 (8.1) | 487 (9.6) | 411 (11.4) | 386 (11.6) | <0.001 |
| Stroke | 126 (3.5) | 143 (2.8) | 118 (3.3) | 126 (3.8) | 0.09 |
| Carotid revascularization | 120 (3.3) | 240 (4.7) | 235 (6.5) | 261 (7.9) | <0.001 |
| Ulcer/gangrene/amputation | 92 (2.5) | 167 (3.3) | 131 (3.6) | 166 (5.0) | <0.001 |
| Lower limb revascularization | 65 (1.8) | 135 (2.7) | 121 (3.4) | 129 (3.9) | <0.001 |
| Comorbidities, n (%) | |||||
| Any | 682 (18.7) | 872 (17.2) | 620 (17.2) | 613 (18.5) | 0.15 |
| COPD | 173 (4.7) | 201 (4.0) | 142 (3.9) | 158 (4.8) | <0.001 |
| Chronic liver disease | 299 (8.2) | 415 (8.2) | 326 (9.0) | 321 (9.7) | 0.06 |
| Cancer | 279 (7.7) | 342 (6.7) | 215 (6.0) | 195 (5.9) | <0.001 |
HbA1c = haemoglobin A1c; C1 = HbA1c <6.5%; C2 = HbA1c 6.5–7.49%; C3 = HbA1c 7.5–8.49%; C4 = HbA1c ≥8.5%; BMI = body mass index; HDL = high-density lipoprotein; LDL = low-density lipoprotein; BP = blood pressure; ACE-I = angiotensin converting enzyme inhibitor; ARB = angiotensin receptor blocker; eGFR = estimated glomerular filtration rate; DKD = diabetic kidney disease; DR = diabetic retinopathy; CVD = cardiovascular disease; COPD = chronic obstructive pulmonary disease.