Archer 2007.

Methods	Randomised controlled trial
Participants	3240 postmenopausal healthy women, with an intact uterus and with a screening biopsy classified as atrophic or inactive endometrium and a double‐layer endometrial thickness ≤ 6 mm as assessed by transvaginal ultrasonography (TVUS). Mean time since menopause: 4.5 years. Mean age: 54.4 years
Interventions	Tibolone 2.5 mg/d Tibolone 1.25 mg/d Continuous combined conjugated equine oestrogen 0.625 mg/d plus medroxyprogesterone acetate 2.5 mg/d Administered for 2 years
Outcomes	Unscheduled bleeding, breast cancer, endometrial cancer, endometrial hyperplasia, ovarian cancer, cardiovascular events, cerebrovascular events, thromboembolic events
Notes	Timing: not reported Location: USA, Europe, Chile Multi‐centre:146 centres
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	No details on random generation of the allocation sequence, but use of an interactive voice response system should keep risk of selection bias very low
Allocation concealment (selection bias)	Low risk	Interactive voice response system
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐dummy method
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not specified but, given the nature of outcomes assessed, their evaluation is likely to be "objective"
Incomplete outcome data (attrition bias) All outcomes	High risk	No information on withdrawals/dropouts
Selective reporting (reporting bias)	Low risk	No difference between study protocol and assessed outcomes
Conflict of interest	High risk	Financed by the drug manufacturer; some study authors are employees of the drug manufacturer