Lv 2005.

Study characteristics
Methods	Randomised controlled trial Location of the trial: quote: Huazhong, China Method of randomisation: unclear, quote: “The subjects were randomized to either the CPA group (n=25) or to the CPA + metformin group (n=25).” Method of allocation concealment: not stated Source of funding: Not stated
Participants	Inclusion criteria: PCOS was defined as the presence of: (1) chronic anovulatory disorders such as oligomenorrhoea, anovulatory cycles, or secondary amenorrhoea; (2) the ratio of LH/FSH was > 2 and (or) the plasma testosterone (T) level was > 2.6 nmol/L; (3) 10 or more follicles (2 mm to 8 mm in diameter) in one or both ovaries by transvaginal ultrasound examination. All the women were euthyroid and had normal prolactin levels. Exclusion criteria: women who had any other known endocrinological disease, and those taking drugs known to affect carbohydrate or lipid metabolism and OGTT results during the 6 months preceding the study were excluded. Number of women randomised: 50 MET + OCP: 25 OCP: 25 Number of women analysed: not stated Number of withdrawal and reasons: not stated Summary characteristics: PCOS, aged 16 to 36 years, all women were either of normal weight or thin BMI (≤ 25 kg/m2). Age (years): OCP + MET mean (+ SD): 24.5 (5.6) OCP mean (+ SD): 24.35 (5.11) BMI (kg/m2): OCP + MET mean (+ SD): 22.1 (2.46) OCP mean (+ SD): 21.81 (1.37)
Interventions	Treatment: OCP (Ethinyl estradiol 35 mcg Cyproterone acetate 2mg) 21 days stop 7 days + MET 500 mg/day Control: OCP (Ethinyl estradiol 35 mcg Cyproterone acetate 2 mg) 21 days stop 7 days Duration: 6 months Co‐intervention(s): Medroxyprogesterone for amenorrhoeic patients
Outcomes	Primary outcomes: noneSecondary outcomes: BMI (kg/m2) Serum total testosterone (nmol/L) Fasting insulin (mIU/L) Fasting glucose (mmol/L) 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. BMI (kg/m2) (b) Hormonal parameters 1. Serum total testosterone (nmol/L) (c) Metabolic parameters 1. Fasting insulin (mIU/L) 2. Fasting glucose (mmol/L) 3. Fasting total cholesterol (mmol/L) 4. Fasting HDL cholesterol (mmol/L) 5. Fasting LDL cholesterol (mmol/L) 6. Fasting triglycerides (mmol/L)
Notes	Authors contacted about: the number of patient randomised in each group and number of withdrawal.Power calculation: unclear
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: “The subjects were randomized to either the CPA group (n=25) or to the CPA + metformin group (n=25).” Insufficient information about the sequence generation process available to permit a judgement of ‘low risk’ or ‘high risk’.
Allocation concealment (selection bias)	Unclear risk	Method of allocation 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	Unclear risk	Paper does not provide any information on participant after randomisation.
Selective reporting (reporting bias)	Low risk	The study protocol is not available but it is clear that the published reports include all expected outcomes, including those that were prespecified.
Other bias	Low risk	The study appears to be free of other sources of bias.