The study was not powered specifically for determining the relative risk of CV events. However, there was some evidence that liraglutide was associated with lower CV risk than the other 3 agents by about 30%. There was no difference in microvascular risk among the agents in this study of relatively short-term disease. Side effects were not a major problem and no different than expected. Glargine and glimepiride were associated with less weight loss, while liraglutide had a particular benefit on weight. Glimepiride is associated with significantly more frequent incidents of severe hypoglycemia, though the rates of severe hypoglycemia were quite low. Liraglutide users reported significantly higher rates of nausea and had a higher early drop-out rate, but did not show a difference in continued use by the end of the study.
In summary, the GRADE trial confirmed that glucose control in T2D is a progressive problem, as the addition of all 4 classes of medication failed to keep most patients in the target glucose range. However, basal insulin and GLP-1 RAs outperformed the other 2 classes. Sitagliptin has the poorest metabolic profile. One could argue that, based on overall metabolic control and concomitant weight benefits, less need for glucose monitoring, simple titration, apparent CV benefit, and insignificant hypoglycemia, GLP-1 RAs offer the best option as an agent to add to metformin. This conclusion is fortified by the fact that the agent used to represent this class in the study appears to be less effective in reducing glucose and weight and offers less convenience than the newer, once-weekly GLP-RAs available today.