Table 1.

Systematic review of randomized controlled trials evaluating the effects of metformin in overweight women with polycystic ovary syndrome.

Author	Sample size (T/C)	Mean age (T/C)	BMI (T/C)	Nation	Intervention	Control	Metformin intervention			Outcome measured
							Frequency (per day)	Dose (mg)	Duration (week)
Curi et al. [22]	20/20	24.6 ± 1.3/26.3 ± 1.4	31.1 ± 1.5/31.8 ± 1.6	Brazil	Metformin	Usual care controls + placebo treatment	2	850 mg	24	①②③④⑤⑥⑬⑭
Esfahanian et al. [23]	17/13	21.9 ± 9.3/20 ± 4.6	31.1 ± 3.3/34.1 ± 5.4	Iran	Metformin	Usual care controls + hypocaloric diet	—	1000 mg/day gradually to 2000 mg/day	12	①②⑦⑧⑨⑩⑪⑫⑬
Otta et al. [24]	15/15	25.47 ± 4.82/24.7 ± 3.46	32.4 + 6.7/35.6 + 4.98	Brazil	Metformin	Usual care controls + placebo treatment	2	750 mg	16	①②④⑤⑦⑧⑨⑩⑪⑫⑬⑭
Gambineri et al. [25]	10/10	26·1 ± 4·5/27·1 ± 3·6	37·0 ± 5·9/37·6 ± 4·1	Italy	Metformin	Usual care controls + placebo treatment	2	850 mg	24	①⑥⑦⑧⑨⑩⑪⑫⑬⑭
Gambineri et al. [26]	20/20	2 8 ± 8/26 ± 5	35 ± 4/37 ± 5	Italy	Metformin	Usual care controls + placebo treatment	2	850 mg	48	①②⑥⑦⑧⑪⑫
Hoeger et al. [27]	9/11	29.5 ± 6.4/27.1 ± 4.5	37.1 ± 4.9/37.1 ± 4.6	United States	Metformin	Usual care controls + placebo treatment	2	850 mg	48	①②⑥
Bonakdaran et al. [28]	17/16	25.9 ± 4.5/25.2 ± 7.9	28.2 ± 5.03/25.3 ± 5.1	Iran	Metformin	Usual care controls + placebo treatment	2	1000 mg	12	①④⑪⑫⑬
Karimzadeh Javedani [29]	90/75	27.33 ± 2.34/27.48 ± 2.69	27.17 ± 1.73/27.92 ± 1.05	Iran	Metformin	Usual care controls + placebo treatment	2	1500 mg	24	①②⑦⑧
Lord et al. [30]	16/16	27.76 ± 4.89/30.63 ± 4.84	33.74 ± 6.74/36.37 ± 7.46	United Kingdom	Metformin	Usual care controls + placebo treatment	3	500 mg	12	①②④⑥⑦⑧⑨⑩⑪⑫⑬
Tang et al. [31]	69/74	29.7 ± 3.7/29.8 ± 3.8	37.6 ± 5.0/38.9 ± 9.5	United Kingdom	Metformin	Usual care controls + placebo treatment	2	850 mg	24	①②⑥⑨⑩⑪⑫⑬
Tiwari et al. [32]	33/33	24.33 ± 3.89/24.46 ± 4.76	25.23 ± 4.64/26.32 ± 3.68	India	Metformin	Usual care controls + fixed exercise	2	850 mg	24	①②⑬
Yarali et al. [33]	32/32	29.7 ± 5.6/28.4 ± 5.1	28.6 ± 4.0/29.6 ± 4.8	Turkey	Metformin + rFSH	Usual care controls + placebo treatment	2	850 mg	6	①②③⑤⑫⑬⑭

Months were converted to weeks by using 1 month = 4 weeks; years were converted by using 1 year = 52 weeks. BMI: body mass index; WC: waist circumference; FSH: follicle-stimulating hormone; HOMA-IR: homeostasis model assessment of insulin resistance; LH: luteinizing hormone; SHBG: sex hormone-binding globulin; HDL: high-density lipoprotein; LDL: low-density lipoprotein; TC: total cholesterol; TG: triglycerides; and FBG: fasting blood glucose. ① BMI; ②WC; ③ FSH; ④ HOMA-IR; ⑤ LH; ⑥SHBG; ⑦ HDL; ⑧ LDL; ⑨ TC; ⑩ TG; ⑪ FBG; ⑫ fasting insulin;⑬ testosterone; and ⑭ androstenedione.