Glycaemic control and plasma lipoproteins in menopausal women with Type 2 diabetes treated with oral and transdermal combined hormone replacement therapy

Aims: To compare the effect of a fixed combination of an oestrogen (17-β oestradiol) with a cyclical progestagen (norethisterone) on glycaemic control, plasma lipoproteins and haemostatic factors in women with Type 2 diabetes.

Methods: Oral and transdermal hormone replacement therapy (HRT) were compared to no HRT treatment in 33 postmenopausal women with Type 2 diabetes, in a 12-week randomised prospective open parallel group study.

Results: In the 11 women who received 12 weeks of oral HRT, there was a significant fall in total cholesterol (5.9 ± 1.0 (S.D.) to 4.7 ± 1.0 mmol l^-1, P = 0.005), low density lipoprotein cholesterol (3.44 ± 0.89 to 2.77 ± 0.92 mmol l^-1, P = 0.005) and triglyceride values (median (range)), (2.46 (0.96-5.52) to 2.29 (1.00-3.87) mmol l^-1, P < 0.05). Oral HRT improved glycated haemoglobin (HbA_1c) (7.4 ± 1.4 to 6.8 ± 1.2%, P ≤ 0.005). Oral HRT additionally reduced the cell adhesion factor E-selectin (82 ± 33 to 60 ± 20 μg l^-1, P < 0.01) and factor VII (143 ± 25 to 109 ± 24% pooled plasma activity, P < 0.01). No improvement in any of these parameters, except E-selectin (65 ± 19 to 58 ± 18 μg l^-1, P < 0.01), occurred in the nine women receiving transdermal HRT, and no improvement occurred in the 13 controls randomised to no treatment.

Conclusion: In women with Type 2 diabetes, cyclical oestrogen and progestagen taken orally for 12 weeks significantly improved glycaemic control and lipoprotein concentrations. These metabolic benefits were not apparent when a similar HRT preparation was administered transdermally.