Metformin is associated with improved left ventricular diastolic function measured by tissue Doppler imaging in patients with diabetes

Objective: To examine the association between selected glucose-lowering medications and left ventricular (LV) diastolic function in patients with diabetes. Design: Retrospective cohort study (years 2005-2008). Methods: Echocardiograms of 242 patients with diabetes undergoing coronary angiography were analyzed. All patients had an LV ejection fraction (LVEF) >= 20% and were without atrial fibrillation, bundle branch block, valvular disease, or cardiac pacemaker. Patients were grouped according to the use of metformin (n=56), sulfonylureas (n=43), insulin (n=61), and combination treatment (n=82). Results: Mean age (66 +/- 10 years) and mean LVEF (45 +/- 11%) were similar across the groups. Mean isovolumic relaxation time (IVRT) was 66 +/- 31, 79 +/- 42, 69 +/- 23, and 66 +/- 29 ms in metformin, sulfonylureas, insulin, and combination treatment groups respectively (P=0.4). Mean early diastolic longitudinal tissue velocity (e') was 5.3 +/- 1.6, 4.6 +/- 1.6, 5.3 +/- 1.8, and 5.4 +/- 1.7 cm/s in metformin, sulfonylureas, insulin, and combination treatment groups (P=0.04). In adjusted linear regression models, the use of metformin was associated with a shorter IVRT (parameter estimate -9.9 ms, P=0.049) and higher e' (parameter estimate +0.52 cm/s, P=0.03), compared with no use of metformin. The effects of metformin were not altered by concomitant use of sulfonylureas or insulin (P for interactions >0.4). Conclusions: The use of metformin is associated with improved LV relaxation, as compared with no use of metformin.