Endrikat 2009.

Study characteristics
Methods	A multicentre (9 centres in Canada) parallel‐group open‐label RCT
Participants	Inclusion criteria Otherwise healthy women Aged > 30 years at entry Diagnosis of idiopathic menorrhagia Normal or only slightly enlarged uterus Exclusion criteria Contraindications for LNG‐IUS and combined oral contraceptive pills Metabolic and endocrine diseases Diagnostically unclassified genital bleeding History of liver or vascular diseases Concomitant use of medications that could influence study objectives Intramural or subserous fibroids of mean diameter ≥ 4 cm or submucous fibroids, adenomyosis, or endometrial abnormalities (verified by saline infusion sonography or hysteroscopy) Perimenopausal women (as evidenced by serum FSH levels > 50 IU/L and serum estradiol levels < 100 pmol/L) Mean (SD) age: 41.8 (4.3) in LNG‐IUS group; 42.2 (4.4) in combined oral contraceptives group
Interventions	Levonorgestrel‐releasing intrauterine system (LNG‐IUS) (Mirena) (n = 20): released up to 20 µg of LNG per 24 hours; inserted within 7 days of the start of the menstrual period Combined oral contraceptives (COC) (Minestrin) (n = 19): 28 tablets per cycle, with the first 21 tablets containing 1 mg of NETA and 20 µg of ethinyl estradiol (EE) and the last 7 tablets containing placebo Duration: 12 months
Outcomes	Primary: MBL (assessed by PBAC) Secondary: Rx success (MBL score < 100 at 12 months); Hb; quality of life (menorrhagia severity score); adverse events
Notes	Three of the authors (including the principal author) were employees of a pharmaceutical company (which also funded the study)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Participating subjects were randomised in order of arrival at the treatment centre" according to computer‐generated randomisation list
Allocation concealment (selection bias)	Low risk	Centralisation of randomisation sequence; and (quote): "a randomised subject could not be replaced by another subject"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not possible; outcomes likely to be influenced
Blinding of participants and personnel (performance bias) Haematin alkaline, Haemoglobin All outcomes	Low risk	Blinding not possible; outcome unlikely to be influenced
Blinding of outcome assessment (detection bias) All outcomes	High risk	Blinding not possible; outcomes likely to be influenced
Blinding of outcome assessment (detection bias) (Haematine alkaline and haemoglobin) All outcomes	Unclear risk	Blinding not possible; outcome unlikely to be influenced
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcomes assessed in the full analysis set (FAS) population and compared with per protocol analyses
Selective reporting (reporting bias)	Low risk	Measures of variation in the estimates not reported in the publication but the authors supplied a copy of the full report
Other bias	High risk	Three of the authors (including the principal author) were employees of a pharmaceutical company (which also funded the study), groups similar at baseline