Given the high profile of failures of recent 'blockbuster' drugs in Type 2 diabetes it is not surprising there is anxiety about the risks associated with newer drugs.
In a recent meta-analysis of trials of glucagon-like-peptide 1 receptor agonists (trials that were originally designed to assess metabolic outcomes) the authors conclude there was no evidence to suggest a "detrimental effect of GLP-1 receptor agonists on cardiovascular events. Specifically designed longer-term trials are needed to verify the possibility of a beneficial effect." 
1. Monami M, Cremasco F, Lamanna C, Colombi C, Desideri CM, Iacomelli I, Marchionni N, Mannucci E. Glucagon-like peptide-1 receptor agonists and cardiovascular events: a meta-analysis of randomized clinical trials. Exp Diabetes Res 2011;2011:215764. Available from: http://www.ncbi.nlm.nih.gov/pubmed/21584276