Similar cardiovascular outcomes in patients with diabetes and established or high risk for coronary vascular disease treated with dulaglutide with and without baseline metformin.

OBJECTIVE: Recent European Guidelines for Diabetes, Prediabetes and Cardiovascular Diseases introduced a shift in managing patients with type 2 diabetes at high risk for or established cardiovascular (CV) disease by recommending GLP-1 receptor agonists and SGLT-2 inhibitors as initial glucose-lowering therapy. This is questioned since outcome trials of these drug classes had metformin as background therapy. In this post hoc analysis, the effect of dulaglutide on CV events was investigated according to the baseline metformin therapy by means of a subgroup analysis of the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) trial. RESEARCH DESIGN AND METHODS: Patients in REWIND (n = 9901; women: 46.3%; mean age: 66.2 years) had type 2 diabetes and either a previous CV event (31%) or high CV risk (69%). They were randomized (1:1) to sc. dulaglutide (1.5 mg/weekly) or placebo in addition to standard of care. The primary outcome was the first of a composite of nonfatal myocardial infarction, nonfatal stroke, and death from cardiovascular or unknown causes. Key secondary outcomes included a microvascular composite endpoint, all-cause death, and heart failure. The effect of dulaglutide in patients with and without baseline metformin was evaluated by a Cox regression hazard model with baseline metformin, dulaglutide assignment, and their interaction as independent variables. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by a Cox regression model with adjustments for factors differing at baseline between people with vs. without metformin, identified using the backward selection. RESULTS: Compared to patients with metformin at baseline (n = 8037; 81%), those without metformin (n = 1864; 19%) were older and slightly less obese and had higher proportions of women, prior CV events, heart failure, and renal disease. The primary outcome occurred in 976 (12%) participants with baseline metformin and in 281 (15%) without. There was no significant difference in the effect of dulaglutide on the primary outcome in patients with vs. without metformin at baseline [HR 0.92 (CI 0.81-1.05) vs. 0.78 (CI 0.61-0.99); interaction P = 0.18]. Findings for key secondary outcomes were similar in patients with and without baseline metformin. CONCLUSION: This analysis suggests that the cardioprotective effect of dulaglutide is unaffected by the baseline use of metformin therapy.

Endothelium-dependent and -independent vascular dysfunction in type 1 diabetes: role of conventional risk factors, sex, and glycemic control.

OBJECTIVE: Defective NO release/response may contribute to increased coronary risk and the loss of sex difference in coronary heart disease in diabetes. We aimed to determine whether NO release/response is impaired in type 1 diabetes and whether any defects are greater in women than men. METHODS AND RESULTS: Forearm blood flow response to vasoactive drugs was assessed by venous plethysmography in 88 diabetic and 69 control subjects aged 30 to 53 years. In diabetic patients, response was 18% lower for acetylcholine (ACh) (P=0.002), 6% lower for bradykinin (P=0.14), and 17% lower for glyceryl trinitrate (GTN) (P<0.001). Women had a higher response to ACh than men (17%, P=0.006). The diabetes-associated defect in ACh was greater in women (25% lower, P=0.01) than men (13% lower, P=0.08), although not significantly (P=0.26 for the interaction). Poorer glycemic control was associated with ACh response (P=0.003) and contributed to the greater defect in diabetic women than men. CONCLUSIONS: The diabetes-associated defect in GTN response was similar in men and women. Established coronary heart disease risk factors did not explain any of the defects in ACh or GTN response associated with diabetes. Type 1 diabetes is associated with impaired responsiveness to NO and with an impairment in ACh-stimulated NO release.

Von Willebrand factor in type 1 diabetes: its production and coronary artery calcification.

BACKGROUND: Von Willebrand factor (vWF) has generally been regarded as a good predictor of vascular risk. However, no previous studies have examined its relationship with coronary calcification. The aim of this study was to determine whether vWF activity is higher in type 1 diabetic patients than controls; its relationship with cardiovascular risk factors; and to endothelial nitric oxide production and coronary artery calcification. MATERIAL/METHODS: Von Willebrand factor activity was measured in 181 type 1 diabetic patients and 188 controls. Coronary artery calcification was measured by Electron Beam Computed Tomography. Forearm blood flow was measured by venous plethysmography in response to intra-brachial infusion of bradykinin, glyceryl trinitrate, noradrenaline and NG-monomethyl-L-arginine (L-NMMA) in 149 subjects. RESULTS: Von Willebrand factor was significantly increased in diabetic patients compared to controls (median 100% vs 87%, p=0.001). Von Willebrand factor activity was significantly higher in diabetic patients with micro/macroalbuminuria than those with normoalbuminuria (109% vs 93%, p<0.001). Among diabetic subjects, being in the top quartile for vWF was associated with a lower response to L-NMMA (p=0.009). There was no association between vWF activity and coronary artery calcification in either the diabetic (p=0.9) or control group (p=0.8). CONCLUSIONS: Cardiovascular risk factors including albuminuria do not explain the high vWF activity in type 1 diabetic patients. There is some evidence that vWF correlates with endothelial nitric oxide production. The lack of correlation with coronary artery calcification indicates that vWF is not a useful marker of atheroma burden.