Table 1.
Characteristics of included studies and study participants
| Authors and year of study [reference] | Intervention group; control group | Met/control (n) | Inclusion criteria | Follow-up (months) | Age (years) | BMI (kg/m2) | Diabetes duration (years) | HbA1c (%) | HbA1c (mmol/mol) | Male (%) |
|---|---|---|---|---|---|---|---|---|---|---|
| Chiasson et al 2001a [24] | Met; Plac | 83/83 | Diet alone, HbA1c 7.2–9.5% (55.2–80.3 mmol/mol) | 36 | 57.9 | 30.7 | 7.5 | 8.2 | 66.1 | 73.5 |
| Chiasson et al 2001b [24] | Met + Mig; Mig + Plac | 76/82 | Diet alone, HbA1c 7.2–9.5% (55.2–80.3 mmol/mol) | 36 | 58.9 | 29.5 | 6.1 | 8.3 | 67.2 | 77.6 |
| DeFronzo et al 1995a [25] | Met; Plac | 143/146 | Obese, diet alone | 7 | 53.0 | 29.9 | 6.0 | 8.4 | 68.3 | 43.4 |
| DeFronzo et al 1995b [25] | Met + Glib; Glib + Plac | 213/209 | OW/obese, FBG > 7.8 mmol/l | 7 | 55.0 | 29.0 | 7.8 | 8.8 | 72.7 | 46.0 |
| Hällsten et al 2002 [19] | Met; Plac | 13/14 | New diagnosis or diet alone, FBG 6.1–11.0 mmol/l | 6 | 57.8 | 29.9 | 0.0 | 6.9 | 51.9 | 61.5 |
| Hermann et al 2001 [20] | Met + Ins; Plac + Ins | 16/19 | OW/obese, on Ins, HbA1c > reference +2%b | 12 | 56.9 | 33.6 | 13.0 | 9.1 | 76.0 | 43.8 |
| Holman et al 2008 [21] | Met; diet | 342/411 | OW/obese, FBG > 6.1–15.0 mmol/l | 212 | 53.0 | 31.6 | 0.0 | 7.3 | 56.3 | 45.9 |
| Horton et al 2000a [26] | Met; Plac | 178/172 | HbA1c 6.8–11% (50.8–96.7 mmol/mol) | 6 | 56.8 | 29.6 | 4.5 | 8.4 | 68.3 | 68.0 |
| Horton et al 2000b [26] | Met + Nat; Met + Plac | 172/179 | HbA1c 6.8–11% (50.8–96.7 mmol/mol) | 6 | 58.4 | 30.0 | 4.5 | 8.4 | 68.3 | 58.7 |
| Kooy et al 2009 [22] | Met + Ins; Plac + Ins | 196/194 | On ins | 51 | 64.0 | 30.0 | 14.0 | 7.9 | 62.8 | 41.3 |
| Rachmani et al 2002 [27] | Continue Met; stop Met | 195/198 | Met, creatinine 132–220 μmol/l, HF, raised LFTs | 48 | 65.0 | 28.7 | 15.0 | 8.6 | 70.5 | 52.8 |
| UKPDS 1998 [12] | Met + Sul; Sul | 268/269 | FBG 6.1–15.0 mmol/l on Sul | 79 | 59.0 | 29.7 | 7.1 | 7.5 | 58.5 | 57.2 |
| Gram et al 2011 [23]a | Met +/− Asp Ins +/− Ros +/− NPH Ins; Plac +/− Asp Ins +/− Ros +/− NPH Ins | 184/187 | HbA1c > 7.0% (53.0 mmol/mol), BMI > 25 kg/m2 | 24 | 56.0 | 34.2 | 8.5 | 8.6 | 70.5 | 64.1 |
aFactorial design
bAn inclusion criterion of an HbA1c value higher than the upper reference limit + 2% (21.8 mmol/mol)
Asp Ins, insulin aspart; FBG, fasting blood glucose; Glib, glibenclamide (known as glyburide in the USA and Canada); HF, heart failure (NYHA class 3–4); Ins, insulin; LFT, liver function test; Met, metformin; Mig, miglitol; Nat, nateglinide; OW, overweight; Plac, placebo; Ros, rosiglitazone; Sul, sulfonylurea