Acarbose

Chiasson J L, et al. The Lancet, 2002, 359(9323), 2072-2077.

This study looked at whether acarbose prevented or delayed impaired glucose tolerance to become type 2 diabetes. The result was that acarbose could be supplemented or a substitute, for lifestyle modifications to delay type 2 diabetes in patients with impaired glucose tolerance.
· Methods
In a randomized, multicenter, placebo-controlled, randomized study, patients with impaired glucose tolerance received 100 mg of acarbose or placebo three times daily. The primary outcome measure was development of diabetes based on annual oral glucose tolerance test (OGTT).
· Results
A randomized trial involved 714 patients with impaired glucose tolerance assigned to the acarbose group and 715 to the placebo group. In the end, 211 out of 682 patients (31%) in the acarbose group and 130 out of 686 patients (19%) in the placebo group discontinued the treatment early. Among those treated with acarbose, 221 patients (32%) developed diabetes, compared to 285 patients (42%) in the placebo group, giving a relative risk of 0.75 (95% CI 0.63-0.90; p=0.0015). Additionally, acarbose was effective in reverting impaired glucose tolerance back to normal (p<0.0001). At the study's conclusion, a three-month course of placebo was observed an increase in the progression from impaired glucose tolerance to diabetes. The most common side effects associated with acarbose were flatulence and diarrhea.

Zhang Y Y, et al. Experimental and Clinical Endocrinology & Diabetes, 2014, 122(06), 373-378.

To find out if acarbose was effective in polycystic ovary syndrome (PCOS) patients, a meta-analysis of the impact of acarbose on PCOS was performed. It was determined from the data that acarbose decreased testosterone, triglycerides (TG) and very low-density lipoprotein (VLDL) and enhanced high-density lipoprotein (HDL). However, these results are not conclusive given the small size of the randomized controlled trials and the poor quality of the included randomized controlled trials.
A meta-analysis of three of these studies found that acarbose was more effective than placebo or no treatment at decreasing serum testosterone. Yet acarbose also had a significantly higher rate of adverse effects such as abdominal cramps and diarrhoea. No significant changes were observed in the Ferriman-Gallwey score or body mass index (BMI).
Two studies meta-analysed found that acarbose was better than placebo or nothing for lowering TG (Worsted Mean Difference [WMD] = 18.18, 95% CI: 36.30 to 0.06, P = 0.05) and VLDL cholesterol (WMD = 6.49, 95% CI: 9.14 to 3.84, P < 0.00001) and increasing HDL cholesterol (WMD = 5.14, 95% CI: 1.73 to 8.55, P = 0.003).
There was no significant difference between acarbose and metformin for increased ovulation, periods, serum testosterone, side effects or BMI.