Baseline characteristics of participants
| Characteristics | Total (n=145) | No vitamin B12 deficiency (n=113) | Vitamin B12 deficiency (n=32) | P value |
| Age (years) | 61.5±11.0 | 60.6±11.0 | 64.5±10.7 | 0.075 |
| Mean±SD | ||||
| Gender | 0.844 | |||
| Women, N (%) | 75 (51.7) | 59 (52.5) | 16 (50) | |
| Men, N (%) | 70 (48.3) | 54 (47.8) | 16 (50) | |
| BMI (kg/m2) | 22.9±1.9 | 22.9±2.1 | 22.8±1.5 | 0.755 |
| Mean±SD | ||||
| Hypertension | 0.031 | |||
| Yes, N (%) | 105 (61.9) | 77 (68.1) | 28 (87.5) | |
| No, N (%) | 40 (38.1) | 36 (31.9) | 4 (12.5) | |
| Diabetic peripheral neuropathy | 0.972 | |||
| Yes, N (%) | ||||
| No, N (%) | 54 (37.2) | 42 (37.2) | 12 (37.5) | |
| 91 (62.8) | 71 (62.8) | 20 (62.5) | ||
| Diabetes duration (years) | 10.0 (6.0–10.0) | 10.0 (5.5–15.0) | 12.0 (10.0–15.0) | 0.029 |
| Median(Q1–Q3) | ||||
| Metformin use duration (years) | 10.0 (6.0–10.0) | 10.0 (5.5–15.0) | 12.0 (10.0–15.0) | 0.044 |
| Median(Q1–Q3) | ||||
| Metformin dose (mg) | 1700.0 (1000.0–1850.0) | 1700.0 (1000.0–1700.0) | 1700.0 (1700.0–2000.0) | 0.001 |
| Median(Q1–Q3) | ||||
| Hb (g/dL) | 13.6±1.6 | 13.6±1.6 | 13.4±1.5 | 0.674 |
| Mean±SD | ||||
| MCV (fL) | 87.6±6.6 | 87.1±7.0 | 89.5±5.1 | 0.071 |
| Mean±SD | ||||
| Fasting plasma glucose (mg/dL) | 158.4±72.1 | 162.4±77.2 | 144.2±48.2 | 0.208 |
| Mean±SD | ||||
| HbA1c (%) | 8.1±1.9 | 8.3±2.0 | 7.4±1.6 | 0.021 |
| Mean±SD | ||||
| Creatinine (mg/dL) | 0.9(0.7–1.0) | 0.9 (0.7–1.0) | 0.9 (0.8–1.0) | 0.274 |
| Median(Q1–Q3) | ||||
| Total cholesterol (mmol/L) | 146.0 (114.0–180.0) | 148.0 (114.5–181.5) | 138.0 (107.3–164.5) | 0.292 |
| Median(Q1–Q3) | ||||
| Triglyceride (mmol/L) | 163.0 (109.5–238.0) | 163.0 (107.0–231.0) | 162.0 (131.8–307.3) | 0.166 |
| Median(Q1–Q3) | ||||
| HDL-C (mmol/L) | 44.0 (38.0–51.0) | 44.0 (39.0–52.0) | 44.0 (35.0–49.0) | 0.425 |
| Median(Q1–Q3) | ||||
| LDL-C (mmol/L) | 75.0 (49.5–107.5) | 77.0 (53.8–112.5) | 64.2 (48.2–94.9) | 0.242 |
| Median(Q1–Q3) | ||||
| Vitamin B12 level (pg/mL) | 478.0 (323.0–608.0) | 514.0 (416.0–667.5) | 233.0 (196.5–273.8) | < 0.001 |
| Median(Q1–Q3) | ||||
| Folate level (μmol/mL) | 11.5±3.5 | 11.6±3.5 | 11.1±3.5 | 0.457 |
| Mean±SD | ||||
| Insulin treatment | 0.684 | |||
| Yes, N (%) | 50 (34.5) | 38 (33.6) | 12 (37.5) | |
| No, N (%) | 95 (65.5) | 75 (66.4) | 20 (62.5) | |
| Sulfonyl urea treatment | 0.37 | |||
| Yes, N (%) | 45 (31.0) | 33 (29.2) | 12 (37.5) | |
| No, N (%) | 100 (69.0) | 80 (70.8) | 20 (62.5) | |
| DPP4i treatment | 0.089 | |||
| Yes, N (%) | 116 (80.0) | 87 (77.0) | 29 (90.6) | |
| No, N (%) | 29 (20.0) | 26 (23.0) | 3 (9.4) | |
| SGLT2i treatment | 0.161 | |||
| Yes, N (%) | 88 (60.7) | 72 (63.7) | 16 (50.0) | |
| No, N (%) | 57 (39.3) | 41 (36.3) | 16 (50.0) |
BMI, body mass index; DPP4i, dipeptidyl peptidase 4 inhibitor; Hb, haemoglobin; HDL-C, high-density lipoprotein-cholesterol; LDL-C, low-density lipoprotein-cholesterol; MCV, mean cell volume; SGLT2i, sodium-glucose cotransporter 2 inhibitor.