Kaya 2015.

Study characteristics
Methods	Randomised controlled trial Location of the trial: quote: Kayseri, TurkeyMethod of randomisation: quote: "The study population randomized into two different groups.”Method of allocation concealment: not statedSource of funding: Not stated
Participants	Inclusion criteria: PCOS was defined as the presence of two of the following criteria after the exclusion of other aetiologies: (i) polycystic ovaries on ultrasound examination, (ii) chronic oligomenorrhoea or amenorrhoea, (iii) clinical or biochemical evidence of hyperandrogenism Exclusion criteria: exclusion criteria included diabetes mellitus, corticosteroid use, use of drugs affecting insulin resistance, hyperlipidaemia, hypertension, oral contraceptive use, evidence of ongoing infection, presence of severe valve disease, pregnancy, systemic disease (hepatic, renal, cardiac), smoking, aortic disease (coarctation, aneurism, Marfan syndrome or history of aortic surgery). Number of women randomised: 50 MET + OCP: 25 OCP: 25 Number of women analysed: 50 MET + OCP: 25 OCP: 25 Number of withdrawal and reasons: 0 Summary characteristics: PCOS, aged 17‐37 years Age (years): MET + OCP mean (+SD): 24 (4) OCP mean (+SD): 23 (5) BMI (kg/m2): MET + OCP mean (+SD): 29.8 (6.9) OCP mean (+SD): 26.7 (5.7)
Interventions	Treatment: MET 850 mg twice a day + OCP (Ethinyl estradiol 3mcg drospirenone 3 mg) 21days then 7 days placebo Control: OCP (Ethinyl estradiol 3 mcg drospirenone 3 mg) 21days then 7 days placebo Duration: 6 months Co‐intervention(s): none
Outcomes	Primary outcomes: None Secondary outcomes: Body weight (kg) BMI (kg/m2) Blood pressure (systolic) (mm Hg) Blood pressure (diastolic) (mm Hg) Serum total testosterone (nmol/L) Free androgen index (FAI) (%) Fasting total cholesterol (mmol/L) Fasting HDL cholesterol (mmol/L) Fasting LDL cholesterol (mmol/L) Fasting triglycerides (mmol/L)
Subjective outcomes	None
Objective outcomes	(a) Clinical parameters 1. Body weight (kg) 2. (BMI (kg/m2) 3. Blood pressure (systolic) (mm Hg) 4. Blood pressure (diastolic) (mm Hg) (b) Hormonal parameters 1. Serum total testosterone (nmol/L) 2. Free androgen index (FAI) (%) (c) Metabolic parameters 1. Fasting total cholesterol (mmol/L) 2. Fasting HDL cholesterol (mmol/L) 3. Fasting LDL cholesterol (mmol/L) 4. Fasting triglycerides (mmol/L)
Notes	Authors contacted about: testosterone because expressed in the wrong unit. Power calculation: unclear
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: “Then, the study population randomized into two different groups.” Method of randomisation not described. Insufficient information about the sequence generation process available to permit a judgment of ‘low risk’ or ‘high risk’.
Allocation concealment (selection bias)	Unclear risk	Method of concealment not stated. Insufficient information available to permit a judgement of ‘low risk’ or ‘high risk’.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Insufficient information available to permit a judgement of ‘low risk’ or ‘high risk’. Blinding not stated.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information available to permit a judgement of ‘low risk’ or ‘high risk’. Blinding not stated.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data.
Selective reporting (reporting bias)	Unclear risk	Insufficient information available to permit a judgement of ‘low risk’ and ‘high risk’. Protocole not available and measurements are not described in the methods.
Other bias	Low risk	The study appears to be free of other sources of bias.