Table 3 Baseline characteristics of participants with type 1 diabetes by treatment group

From: Effect of metformin on insulin resistance in adults with type 1 diabetes: a 26-week randomized double-blind clinical trial

Characteristic

Metformin (N = 20)

Placebo (N = 20)

Age (year)

38.1 ± 7.1

36.7 ± 10.4

Sex (% male)

60

60

BMI (kg/m2)

27.0 ± 3.7

25.8 ± 3.8

WHR

0.88 ± 0.1

0.90 ± 0.1

Men

0.93 ± 0.1

0.93 ± 0.1

Women

0.81 ± 0.1

0.83 ± 0.0

Blood pressure (mmHg)

  

Systolic

117 ± 13

121 ± 12

Diastolic

73 ± 7

73 ± 8

Medication use (n, [%])

  

Anti-hypertensive

1 (5)

3 (15)

Statin

5 (25)

5 (25)

Hormonal contraception

3 (15)

5 (25)

Family history (n, [%])

  

Type 2 diabetes

3 (15)

5 (25)

Ischaemic heart disease

3 (15)

2 (10)

Ethnicity (% Caucasian)

20 (100)

20 (100)

Glycemia and insulin

  

HbA1c (%)

7.4 ± 0.8

7.6 ± 1.1

Insulin units/kg/daya,b

0.54 (0.47, 0.64)

0.66 (0.52, 0.93)

Insulin delivery method (n, %)

  

MDI

11 (55)

11 (55)

CSII

9 (45)

9 (45)

CGM time in range (%)b

  

<3.0 mmol/L (<55 mg/dL)

0.3 (0.0, 1.7)

0.2 (0.0, 1.1)

<3.9 mmol/L (<70 mg/dL)

2.5 (0.8, 6.3)

1.5 (0.6, 3.9)

3.9–10.0 mmol/L (70–180 mg/dL)

58.5 ± 17.9

58.0 ± 20.5

>10 mmol/L (>180 mg/dL)

37.4 ± 19.1

39.4 ± 21.8

>13.9 mmol/L (>250 mg/dL)

15.0 (3.0, 20.2)

12.5 (4.0, 26.0)

Mean glucose (mmol/L)

9.3 ± 1.6

9.6 ± 2.0

Mean overnight glucose (2400–0600, mmol/L)

8.9 ± 2.1

9.4 ± 2.3

Mean daytime glucose (0600-2400, mmol/L)

9.5 ± 1.6

9.7 ± 1.9

CV (%)

36.6 ± 7.4

35.4 ± 5.6

Diabetes

  

Duration (years)

24.2 ± 8.5

21.7 ± 9.3

Retinopathy (n, %)b

8 (40.0)

8 (40.0)

Mild non-proliferative

7 (35.0)

4 (20.0)

Moderate non-proliferative

1 (5.0)

4 (20.0)

Severe non-proliferative

0 (0.0)

0 (0.0)

Proliferative

0 (0.0)

0 (0.0)

Maculopathy (n, %)

2 (20)

3 (15)

Urine ACR elevatedb (n,%)

1 (5.6)

1 (5.5)

c-peptide <0.03 nmol/L (n, %)

19 (95)

19 (95)

Body composition

  

DEXA

  

Total fat mass (kg)

25.5 ± 10.7

22.6 ± 7.3

Total fat free mass (kg)

55.8 ± 9.4

55.1 ± 10.0

Visceral adipose tissue (kg)

0.4 (0.2, 0.7)

0.5 (0.1, 1.1)

MRIb

  

Mean anterior thigh muscle fat infiltration (%)

4.0 ± 1.3

4.0 ± 0.8

Abdominal subcutaneous adipose tissue volume (L)

7.3 (3.9, 10.4)

4.4 (3.1, 6.4)

Liver fat (%)

1.3 (0.9, 1.5)

1.9 (0.9, 2.8)

Transient elastography

  

CAP score (dB/m)

222 ± 31

238 ± 41

Blood metabolites

  

Total cholesterol (mmol/L)

4.4 ± 0.8

4.2 ± 0.8

LDL (mmol/L)

2.7 ± 0.7

2.5 ± 0.6

HDL (mmol/L)

1.3 ± 0.3

1.4 ± 0.5

Cholesterol/HDL ratio

3.4 ± 0.6

3.3 ± 0.8

Non-HDL (mmol/L)

3.0 ± 0.7

2.9 ± 0.6

Triglycerides (mmol/L)

0.8 ± 0.4

0.8 ± 0.4

Adiponectin (µg/mL)

4.2 (3.4, 13.0)

5.6 (2.5, 9.3)

GDF15* (pg/mL)

553 (471, 675)

642 (474, 688)

Inflammatory and vascular

  

Augmentation index (AIx, %)

10.8 (7.1, 16.5)

13.0 (8.1, 21.6)

sICAM-1 (ng/mL)

214.4 ± 47.5

213.4 ± 49.1

sE-selectin (ng/mL)

34.6 ± 14.4

35.4 ± 14.5

IL-6 (pg/mL)

1.1 (0.7, 1.7)

1.0 (0.7, 1.5)

  1. Values are mean ± SD. Bracket values are median and interquartile range. Hormonal contraception refers to oral and implanted contraceptives. Elevated albumin-to-creatinine ratio defined as ≥2.5 men, ≥3.5 women. To convert the values for HbA1c to mmol/mol, multiple the value by 10.93 then subtract 23.5.
  2. ACR Albumin-to-creatinine ratio, CGM continuous glucose monitoring, CSII continues subcutaneous insulin infusion, CV coefficient of variation, GDF15 growth/differentiation factor-15, HDL high density lipoprotein, IL-6 interleukin 6, LDL low density lipoprotein, MDI multiple daily injection, sE-selectin soluble endothelial selectin, sICAM1 soluble intercellular adhesion molecule 1.
  3. aThere was an imbalance in total daily insulin dose between groups (t-test p = 0.02).
  4. bData available for insulin dose metformin n = 19, placebo n = 19, CGM metformin n = 20, placebo n = 17, urine ACR metformin n = 18, placebo n = 19, high-dose insulin phase metformin n = 20, placebo n = 19, MRI metformin n = 11, placebo n = 12, GDF15 metformin n = 19, placebo n = 20.
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