Beta-blocker use in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular (CV) risk factors is associated with an increased risk of CV events and severe hypoglycemia, according to a recent study.
“Using the ACCORD trial data, this study demonstrated that the use of β-blockers was associated with an increased risk for cardiovascular events and severe hypoglycemia in the modern era. Furthermore, a similar relationship between the use of β-blockers and cardiovascular events was found in patients with heart disease. The indication of β-blockers may need to be reconsidered when this connection is elucidated through future higher-level evidence,”1 wrote lead author Hiroshi Kajio, MD, PhD, of the National Center for Global Health and Medicine, Tokyo, Japan, and colleagues.
While appropriate glycemic control can decrease the risk of diabetic complications, going too far may be counterproductive. Results from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) trial suggest that intensive glucose-lowering therapy is associated with increased hypoglycemia and mortality, which led to discontinuation of the trial after 3.5 years.2 One explanation for these results is that intensive glucose lowering can increase hypoglycemic episodes, which in turn are associated with a heightened risk of vascular events and death.
During episodes of severe hypoglycemia, β-blockers may serve a protective function by decreasing hypoglycemia-related cardiac arrhythmias, severe hypertension, and CV events. However, β-blockers themselves can increase the risk of severe hypoglycemia. They may also dampen early warning signs and contribute to hypoglycemia unawareness. β-blockers also may lead to weight gain, which may increase the risk of CV events over time.
This raises the question: How effective are β-blockers in patients with T2DM? To find an answer, researchers performed a post-hoc analysis of data from the ACCORD trial. The study took place in 77 clinical centers in the US and Canada and included 10,251 people with T2DM, inadequately controlled hemoglobin A1c, and preexisting CV disease (or at increased risk for it).
Participants were randomized to intensive glucose-lowering therapy or standard therapy. The mean follow-up time was slightly over 4.5 years.
1. Tsujimoto T, Sugiyama T, Shapiro MF, et al. Risk of cardiovascular events in patients with diabetes mellitus on β-blockers. Hypertension. 2017;70:103-110.
2. Action to Control Cardiovascular Risk in Diabetes Study Group. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med. 2008;358:2545-2559.