Strict glycaemic control improves skin microcirculation in patients with type 2 diabetes: a report from the Diabetes mellitus And Diastolic Dysfunction (DADD) study.

Microcirculatory and endothelial dysfunction are signs of cardiovascular engagement in patients with type 2 diabetes. This study tested whether glucose normalisation may reverse this. Thirty-nine T2DM patients (age 61±7 years, 58% females) with signs of mild diastolic dysfunction were randomised to strict glucose control based on insulin (I-group; n=21) or oral agents (O-group; n=18) for four months. Skin microcirculation was studied with laser Doppler fluxmetry and endothelial function with brachial artery flow-mediated dilatation. Glucose control improved (reduction of HbA(1c) I-group = -0.5%; O-group -0.7%; p=0.69). Microcirculation improved in the entire group (n=39) determined by foot laser Doppler fluxmetry (32.2±13.6 vs. 35.3±13.1 perfusion units; p<0.001) and laser Doppler fluxmetry following heating (68.8±34.0 vs. 69.3±25.1 PU; p=0.007). Improvement was more consistent with oral agents than insulin. Endothelial function expressed as flow-mediated dilatation decreased in the I-group (6.0±2.2 to 4.7±3.0%; p=0.037) but remained unchanged in the O-group (4.8±2.3 to 5.0±3.7%; n.s.). Glycaemic normalisation improved skin microcirculation but not endothelial function in patients with type 2 diabetes with mild cardiovascular engagement.