Can insulin sensitizers be used to treat menstrual irregularities associated with polycystic ovary syndrome (PCOS)?
Metformin, pioglitazone (Actos), and rosiglitazone (Avandia) can be used to improve menstrual cycling in women with PCOS. (Strength of Recommendation [SOR]: A, based on a meta-analysis.) However, metformin is much less effective than oral contraceptives (OCs). (SOR: A, based on a meta-analysis of randomized controlled trials [RCTs].)
A Cochrane review of 44 RCTs (N = 3,992) assessed the effectiveness of insulin-sensitizing drugs in improving reproductive and metabolic outcomes in women with PCOS.1 Improvement in menstrual cycle irregularities was a secondary outcome. Metformin was more effective than placebo in improving the menstrual pattern (eight RCTs, N = 427; odds ratio [OR] = 1.7; 95% confidence interval [CI], 1.1 to 2.6). Pioglitazone (two RCTs, N = 70; OR = 8.9; 95% CI, 2.4 to 33) and rosiglitazone (two RCTs, N = 100; OR = 5.6; 95% CI, 2.2 to 14) also improved the menstrual pattern compared with placebo.
A Cochrane review (six RCTs, N = 174) compared the effectiveness and safety of insulin sensitizers with OCs in improving clinical, hormonal, and metabolic outcomes in women with PCOS.2 In two trials (n = 35), metformin was less effective than OCs in improving menstrual pattern (OR = 0.08; 95% CI, 0.01 to 0.45). Another RCT (n = 46), which was published after the Cochrane review, compared drospirenone/ethinyl estradiol with rosiglitazone.3 Normalization of menstrual pattern was a secondary measure achieved with both therapies (100% of patients receiving OCs had regular menstrual periods vs. 75% of those receiving rosiglitazone; P = .7), but the study was underpowered to detect a clinically meaningful difference.
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