Metformin as Treatment for Overweight and Obese Adults: A Systematic Review

Article Figures & Data

Table 1.

Clinical Features of Studies Included for Review

Source	Subjects	Dosage (mg)	Study Duration	Main Outcome Measure	Treatment Arms	Baseline Parameters
bid = twice a day; WHR = waist-to-hip ratio; BMI = body mass index; tid = 3 times a day.
Charles et al,¹² 2000	168 men	850 bid	3 mo	Lipids and blood pressure	2	WHR ≥0.95
Charles et al,¹³ 1998	457 persons	850 bid	1 y	Fibrinolysis	2	WHR ≥0.95 men  WHR ≥ 0.80 women
Fontbonne et al,¹⁴ 1996	108 men  216 women	850 bid	1 y	Metabolic parameters and fat distribution	2	WHR ≥0.95 men  WHR ≥0.80 women
Guigliano et al,¹⁵ 1993	12 women	850 bid	12 wk x 2	Blood pressure and left ventricular mass	2	BMI 34 ± 0.9
Kantola et al,¹⁶ 2002	15 men  8 women	1,500/d	8 wk	Blood pressure and insulin sensitivity	2	Weight 86.4–87.7 kg
Lawson et al,¹⁷ 1970	34 women	250 tid, 500 tid	8 wk x 4	Weight loss	4	Weight 74.5–125.5 kg
Lehtovorta et al,¹⁸ 2001	20 men  20 women	500 bid	6 mo	Metabolic parameters	2	Weight 87.8–91.0 kg
More et al,l¹⁹ 1999	11 women 8 men	850 bid	6 wk x 2	Glucose disposal	2	BMI 30–48.5 kg  Weight 79.0–159.1 kg
Paolisso et al,²⁰ 1998	30 persons	500 bid, 850 bid	15 d	Food intake	2	WHR 0.83 ± 0.01  BMI 33.1 ± 6.4 kg

Table 2.

Quality Features of Articles Included for Review

Source	Randomized	Double- Blinded	Description of Dropouts	Design	Description of Allocation Concealment	Power Analysis	Intention to Treat
RCT = randomized controlled trial.
Charles et al,¹² 2000	Yes	Yes	Yes	RCT	Indeterminant	Yes	Yes
Charles et al,¹³ 1998	Yes	Yes	Yes	RCT	Indeterminant	No	No
Fontbonne et al,¹⁴ 1996	Yes	Yes	Yes	RCT	Indeterminant	Yes	Yes
Guigliano et al,¹⁵ 1993	Yes	Yes	Yes	Crossover	Indeterminant	Yes	No dropouts
Kantola et al,¹⁶ 2002	Yes	Yes	Yes	RCT	Yes	Yes	No
Lawson et al,¹⁷ 1970	Yes	Yes	Yes	Crossover	Indeterminant	No	No
Lehtovorta et al,¹⁸ 2001	Yes	Yes	Yes	RCT	Indeterminant	Yes	No dropouts
More et al,¹⁹ 1999	Yes	Yes	Yes	Crossover	Indeterminant	No	Yes
Paolisso et al,²⁰ 1998	Yes	Yes	Yes	RCT	Indeterminant	No	No dropouts

Table 3.

Results of Clinical Trials Included for Review

	Weight (kg)		BMI (kg/m²)		Waist-Hip Ratio^†
Source	Metformin	Placebo	Metformin	Placebo	Metformin	Placebo
* Indicates statistically significant (P <.05) difference from baseline.
† A change in ratios cannot be expressed in terms of units.
Charles et al,¹² 2000	−0.50	0.10	—	—	−0.008	−0.015
Charles et al,¹³ 1998	−2.0	−0.8	—	—	—	—
Fontbonne et al,¹⁴ 1996	−2.0*	−0.8	—	—	−0.009*	−0.017
Guigliano et al,¹⁵ 1993	—	—	0	0	0	0
Kantola et al,¹⁶ 2002	−0.2	0.2	—	—	—	—
Lawson et al,¹⁷ 1970	−3.6	−2.22	—	—	—	—
Lehtovorta et al,¹⁸ 2001	−2.6	−1.2	—	—	—	—
More et al,l¹⁹ 1999	−0.6	0.3	−0.3	0.2	0.01	0.05
Paolisso et al,²⁰ 1998	−2.8*	−0.25	−1.0	−0.5	0.2	0.25