Table 1.
Baseline characteristics of study population
| Variable | All patients (n = 63) | Metformin (n = 31) | Placebo (n = 32) | P-value |
|---|---|---|---|---|
| Demographics | ||||
| Age, in years | 64.6 ± 8.4 | 64.5 ± 8.9 | 64.6 ± 8.0 | 0.971 |
| Sex (% of males) | 47 (75) | 26 (84) | 21 (66) | 0.096 |
| Ex-smokers (%) | 3 (5) | 16 (52) | 17 (53) | 0.993 |
| Current smokers (%) | 8 (13) | 4 (13) | 4 (13) | |
| Alcohol consumption (%) | 41 (65) | 19 (61) | 22 (69) | 0.430 |
| Weight, kg | 90.3 ± 12.9 | 93.3 ± 12.9 | 87.3 ± 12.3 | 0.074 |
| Body mass index, kg/m2 | 32.0 ± 3.5 | 32.2 ± 3.4 | 31.9 ± 3.6 | 0.419 |
| Systolic blood pressure, mmHg | 130.6 ± 10.9 | 130.8 ± 10.7 | 130.5 ± 11.2 | 0.903 |
| Diastolic blood pressure, mmHg | 75.8 ± 7.9 | 75.3 ± 8.0 | 76.4 ± 7.9 | 0.591 |
| Pre-diabetes (%) | 50 (79) | 23(74) | 27(84) | 0.326 |
| Insulin resistant (%) | 44(70) | 25(81) | 19(59) | 0.096 |
| Pre-diabetes + insulin resistance (%) | 32 (51) | 17 (55) | 15 (47) | 0.535 |
| Heart rate, b.p.m. | 57.7± 9.1 | 57.6 ± 9.9 | 57.8 ± 8.4 | 0.953 |
| MRI study assessments | ||||
| Absolute LVM, g | 114.8 ± 24.8 | 120.7 ± 20.3 | 109.1 ± 27.6 | 0.064 |
| LVMI (height1.7) | 47.3 ± 8.1 | 48.7 ± 6.5 | 46.0 ± 9.3 | 0.197 |
| Subcutaneous adipose tissue, cm3 | 3332.7 ± 1044.1 | 3371.6 ± 1037.0 | 3301.6 ± 1090.3 | 0.897 |
| Visceral adipose tissue, cm3 | 2422.6 ± 878.5 | 2407.1 ± 881.7 | 2441.8 ± 892.2 | 0.713 |
| Flow-mediated dilatation | ||||
| Response to hyperaemia (%) | 5.3 ± 2.3 | 5.4 ± 2.4 | 5.1 ± 2.1 | 0.690 |
| Response to GTN (%) | 14.8 ± 5.4 | 15.2 ± 4.8 | 14.3 ± 6 | 0.540 |
| Past medical history | ||||
| Myocardial infarction (%) | 32 (51) | 15 (48) | 17 (53) | 0.803 |
| Elective PCI (%) | 15 (24) | 5 (16) | 10 (31) | 0.237 |
| Positive ETT in those without angiogram/previous MI (%) | 11 (18) | 7 (23) | 4 (13) | 0.337 |
| CABG (%) | 8 (13) | 5 (16) | 3 (9) | 0.421 |
| Hypertension (%) | 31 (49) | 15 (48) | 16 (50) | 0.898 |
| Dyslipidaemia (%) | 58 (92) | 28 (90) | 30 (94) | 0.615 |
| Medication | ||||
| ACE inhibitors (%) | 44 (70) | 24 (77) | 20 (63) | 0.197 |
| ARB (%) | 11 (18) | 4 (13) | 7 (22) | 0.348 |
| Beta-blockers (%) | 51 (81) | 24 (77) | 27 (84) | 0.482 |
| Calcium-channel blocker (%) | 14 (22) | 9 (29) | 5 (16) | 0.508 |
| Statins (%) | 57 (91) | 30 (97) | 27 (84) | 0.094 |
| Anti-platelet drugs (%) | 62 (98) | 30 (97) | 32 (100) | 0.306 |
| Laboratory measurements | ||||
| Creatinine, μmol/L | 76.2 ±14.0 | 78.3 ± 12.1 | 73.4 ± 15.1 | 0.504 |
| Urea, mmol/L | 5.9 ± 1.2 | 5.9 ± 0.9 | 5.7 ± 1.2 | 0.743 |
| eGFR, mL/min, MDRD | 91.7 ± 17.6 | 92.0 ± 14.8 | 91.0 ± 20.3 | 0.580 |
| Fasting insulin, mU/L | 17.8 ±10.0 | 19.5 ± 9.6 | 15.2 ± 10.0 | 0.220 |
| Fasting glucose, mmol/L | 5.5 ± 0.6 | 5.5 ± 0.5 | 5.4 ± 0.5 | 0.856 |
| FIRI | 3.8 ± 2.1 | 4.2 ± 2.0 | 3.3 ± 2.2 | 0.263 |
| HbA1c, mmol/mol | 40.2 ± 2.5 | 39.9 ± 2.6 | 40.5 ± 2.5 | 0.279 |
| NTproBNP, pg/mL (median IQR) | 877.2 (1166.4) | 957.8 (1029.1) | 796.5 (1247.0) | 0.490 |
| IL-6 pg/mL (median IQR) | 0.6 (0.39) | 0.6 (0.4) | 0.6 (0.4) | 0.980 |
| Soluble ST2, ng/mL (median IQR) | 18.1 (11.3) | 17.2 (11.5) | 18.9 (11.9) | 0.440 |
| TBARs, µM | 3.0 ±1.2 | 2.9 ±1.5 | 3.1 ±1.2 | 0.520 |
Values are mean ± SD, n (%), or median (IQR).
ACE inhibitor, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blockers; CABG, coronary artery bypass grafting; ETT, exercise tolerance test; eGFR, estimated glomerular filtration rate; FIRI, fasting insulin resistance index; GTN, glyceryl trinitrate; HbA1c, glycated haemoglobin; IL-6, interleukin-6; IQR, inter-quartile range; LVM, left ventricular mass; LVMI, left ventricular mass index; MI, myocardial Infarction; MDRD, modification of diet in renal disease; MRI, magnetic resonance imaging; NTproBNP, N-terminal pro B-type natriuretic peptide; PCI, percutaneous coronary intervention; TBARs, thiobarbituric acid reactive substances.