Cetinkalp 2009.

Study characteristics
Methods	Randomised controlled trial Location of the trial: quote: Izmir, TurkeyMethod of randomisation: quote: "Patients were randomized".Method of allocation concealment: nNot statedSource of funding: not stated
Participants	Inclusion criteria: Rotterdam PCOS Consensus criteriaExclusion criteria: DM, hyperprolactinaemia, congenital adrenal hyperplasia (through ACTH test), thyroid disorders, Cushing syndrome, hypertension, hepatic or renal dysfunction, confounding medications (OCP), antihypertensive medications, insulin sensitising drugs)Number of women randomised: unclear: 100/ 99/ 94 MET: 47 OCP: 33Number of women analysed: 94 MET: 47 OCP: 33Number of withdrawal and reasons: unclear. Could be 0/94 (0%), 5/99 (5%) or 6/100 (6%). Summary characteristics: PCOS, lean young women BMI (kg/m2): MET Mean (± SEM): 25.82 (6.12) OCP Mean (±S EM): 24.72 (4.1)
Interventions	Treatment: MET 2g/day Control: OCP (Ethinyl Estradiol 35 mcg Cyproterone acetate 2 mg) Duration: 4 months Co‐intervention(s): none
Outcomes	Primary outcomes: Hirsutism score Secondary outcomes: Menstrual cyclicity, initiation of menses or significant shortening of cycles Acne – subjective Body weight (kg) BMI (kg/m2) Blood pressure (systolic) (mm Hg) Blood pressure (diastolic) (mm Hg) Serum total testosterone (ng/mL) Fasting insulin (mIU/mL) Fasting glucose (mg/dL) Fasting total cholesterol (mg/dL) Fasting HDL cholesterol (mg/dL) Fasting LDL cholesterol (mg/dL) Fasting triglycerides (mg/dL)
Subjective outcomes	(a) Clinical parameters 1. Acne – subjective 2. Hirsutism score
Objective outcomes	(a) Clinical parameters 1. Menstrual cyclicity, initiation of menses or significant shortening of cycles 2. Body weight (kg) 3. BMI (kg/m2) 4. Blood pressure (systolic) (mm Hg) 5. Blood pressure (diastolic) (mm Hg) (b) Hormonal parameters 1. Serum total testosterone (ng/mL) (c) Metabolic parameters 1. Fasting insulin (mIU/mL) 2. Fasting glucose (mg/dL) 3. Fasting total cholesterol (mg/dL) 4. Fasting HDL cholesterol (mg/dL) 5. Fasting LDL cholesterol (mg/dL) 6. Fasting triglycerides (mg/dL)
Notes	Authors contacted about: fasting insulin because expressed in wrong unit. Power calculation: unclear
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Patients were randomized". Insufficient information about the sequence generation process available to permit judgement of ‘low risk’ or ‘high risk’.
Allocation concealment (selection bias)	Unclear risk	Method of allocation concealment not stated. Insufficient information available to permit 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	Unclear risk	States both n = 100, n = 99 and n = 94 randomised (n = 47 metformin, n = 14 rosiglitazone, n = 33 OCP). Withdrawal could be (0% or n = 5 (5%) or n = 6 (6%), no reasons provided for any withdrawals. Insufficient reporting of attrition/exclusions to permit a judgement of 'low risk' or 'high risk'
Selective reporting (reporting bias)	High risk	Acne, hirsutism and improvement of menstrual patterns are described in the results but not in the methods. One or more primary outcomes have been reported using measurements, analysis methods or subset data THAT WERE NOT PRE‐SPECIFIED. Moreover, from results section of paper, all of the studies pre‐specified (primary and secondary) outcomes that are of interest in the review have been reported in the pre‐specified way with the exception of BP, but not a primary or key outcomes.
Other bias	High risk	Baseline imbalance, MET n = 47, rosiglitazone n = 14, OCP n = 33 which cannot be explained by method of randomisation or allocation concealment or incomplete outcome data.