Baseline characteristics of patients receiving a second-line therapy with or without metformin
| Characteristic | Second-line therapy with MET n=10 055 | Second-line therapy without MET n=1782 | Overall N=11 837 | P value |
| Proportion of patients, % | 84.9 | 15.1 | 100 | |
| Sex, male, n (%) | 5321 (52.9) | 953 (53.5) | 6274 (53.0) | 0.574 |
| Missing, n | 2 | 2 | 4 | |
| Age | ||||
| Years, mean (SD) | 56.2 (11.6) | 57.8 (12.1) | 56.5 (11.7) | 0.179 |
| ≤65 years, n (%) | 7935 (78.9) | 1333 (74.8) | 9268 (78.3) | 0.152 |
| 66–75 years, n (%) | 1704 (16.9) | 327 (18.4) | 2031 (17.2) | |
| ≥76 years, n (%) | 416 (4.1) | 122 (6.8) | 538 (4.5) | |
| Missing, n | 0 | 0 | 0 | |
| BMI, kg/m2, mean (SD) | 30.0 (5.9) | 29.7 (6.3) | 30.0 (6.0) | <0.001 |
| Missing, n | 863 | 140 | 1003 | |
| HbA1c, % | ||||
| Mean(SD) | 8.5 (1.7) | 8.1 (1.8) | 8.4 (1.7) | 0.920 |
| <7.0, n (%) | 1130 (13.9) | 335 (25.5) | 1465 (15.6) | 0.829 |
| 7.0 to <8.0, n (%) | 2559 (31.6) | 392 (29.9) | 2951 (31.3) | |
| 8.0 to <9.0, n (%) | 2012 (24.8) | 272 (20.7) | 2284 (24.3) | |
| ≥9.0, n (%) | 2404 (29.7) | 314 (23.9) | 2718 (28.9) | |
| Missing, n | 1950 | 469 | 2419 | |
| Education level, n (%) | ||||
| No formal education | 290 (3.2) | 44 (2.7) | 334 (3.1) | <0.001 |
| Primary education (1–6 years) | 1599 (17.5) | 228 (14.0) | 1827 (17.0) | |
| Secondary education (7–13 years) | 4262 (46.7) | 847 (52.0) | 5109 (47.5) | |
| >13 years of education | 2971 (32.6) | 510 (31.3) | 3481 (32.4) | |
| Missing, n | 933 | 153 | 1086 | |
| Health insurance, n (%) | ||||
| Private | 1576 (16.8) | 256 (15.8) | 1832 (16.6) | <0.001 |
| Public/governmental | 5288 (56.2) | 767 (47.3) | 6055 (54.9) | |
| Mixed | 279 (3.0) | 51 (3.1) | 330 (3.0) | |
| No insurance | 2264 (24.1) | 549 (33.8) | 2813 (25.5) | |
| Missing, n | 648 | 159 | 807 | |
| Employed or self-employed, n (%) | 4636 (49.2) | 771 (45.9) | 5407 (48.7) | 0.573 |
| Missing | 639 | 102 | 741 | |
| Medical history, n (%) | ||||
| Macrovascular complications | 1380 (13.8) | 259 (14.6) | 1639 (13.9) | 0.001 |
| Missing, n | 31 | 7 | 38 | |
| Microvascular complications | 1755 (17.5) | 384 (21.6) | 2139 (18.1) | 0.010 |
| Missing, n | 12 | 3 | 15 | |
| Chronic kidney disease, n (%) | 329 (3.3) | 117 (6.6) | 446 (3.8) | 0.831 |
| Stage 2 (eGFR 60–89 mL/min/1.73 m2) | 181 (55.0) | 52 (44.4) | 233 (52.2) | <0.001 |
| Stage 3 (eGFR 30–59 mL/min/1.73 m2) | 91 (27.7) | 50 (42.7) | 141 (31.6) | |
| Stage 4 (eGFR 15–29 mL/min/1.73 m2) | 6 (1.8) | 8 (6.8) | 14 (3.1) | |
| Stage 5 (eGFR <15 mL/min/1.73 m2) | 6 (1.8) | 0 (0.0) | 6 (1.3) | |
| Stage unknown | 45 (13.7) | 7 (6.0) | 52 (11.7) | |
| Missing, n | 12 | 3 | 15 | |
| Time since diagnosis, years, mean (SD) | 5.6 (5.1) | 5.3 (4.8) | 5.6 (5.1) | <0.001 |
| Missing, n | 200 | 42 | 242 | |
Data are reported as n (%), unless otherwise stated. Percentages were calculated for all patients with data available; patients with missing data were excluded.
P values were calculated using either a Student’s t-test (continuous variables), χ2 test (categorical variables) or Fisher’s exact test (categorical variables). P values <0.05 were considered statistically significant.
BMI, body mass index; eGFR, estimated glomerular filtration rate; HbA1c, glycated haemoglobin; MET, metformin.