Until recently, a diagnosis of diabetes was considered a relative contraindication for hormone replacement therapy (HRT) in post-menopausal women. This is reflected by an uptake of HRT of only around 10 % (approximately half that in the non-diabetic population). 1,2 However, a recent series of reviews on the subject postulated that, due to their increased risk of vascular disease, postmenopausal women with Type 2 diabetes (Type 2 DM) may derive particular benefit from HRT. [3][4][5] These reviews, extrapolating from results of studies in non-diabetic women, suggested potential improvements in several biochemical pathways relating to atherogenesis in diabetes: insulin resistance and glycaemic control, lipid and lipoprotein concentrations, oxidative stress, and prothrombotic changes. Recently published studies have provided some much needed insights into potential benefits of HRT for post-menopausal women with Type 2 DM.
Turning first to insulin resistance and glycaemic control, two randomized placebo controlled trials 6,7 have provided promising results. Andersson et al. 6 treated 25 women with Type 2 DM with 2 mg 17-β€-oestradiol for 3 months in a double-blind, crossover fashion. As well as conventional exclusion criteria (e.g thromboembolic disease), patients on insulin therapy were omitted from the study. They observed significant reductions of around 20 % in fasting glucose and 14 % reduction in HbA 1c in the oestradiol treated group. C-peptide concentrations also fell by around 16 %, and there was a trend for an increase in whole body glucose disposal. Unfortunately, hepatic glucose production was not assessed in this study. Brussard et al. 7 also examined the metabolic effects of 2 mg 17-β€-oestradiol in a similar group of patients for a shorter period (6 weeks), but employed a more straightforward double-blind design, and in addition excluded patients on metformin therapy. Nevertheless, the results were consistent, demonstrating a smaller (3.5 %) but significant reduction in HbA 1c . There was no effect of oestrogen replacement on whole body glucose disposal but suppression of hepatic glucose production by insulin was significantly enhanced, particularly in those patients with triglyceride levels less than 2.0 mmol l -1 at baseline. In both studies weight increased slightly but significantly with oestradiol treatment, suggesting the improvements in glucose metabolism were unrelated to changes in BMI.