Associations between β-blocker therapy and cardiovascular outcomes in patients with diabetes and established cardiovascular disease

Background: The effects of β-blocker therapy in patients with type 2 diabetes (T2D) and established atherosclerotic cardiovascular disease (ASCVD) are unclear. We sought to evaluate associations between β-blocker use in T2D with ASCVD and cardiovascular (CV) outcomes. Methods: In patients with T2D and ASCVD enrolled in the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS), an inverse probability of treatment-weighted Cox proportional hazards model was used to examine the association between baseline β-blocker therapy (at randomization) and the primary CV composite (defined as CV death, non-fatal myocardial infarction [MI], non-fatal stroke, or hospitalization for unstable angina), including in subgroups with prior MI and heart failure (HF); other outcomes evaluated included individual components of the primary composite, hospitalization for HF, and severe hypoglycemic events. Results: Of the 14,671 patients randomized, 9322 (64%) were on a β-blocker at baseline; these patients were more likely to have prior MI or HF. Over a median 3.0 (25th, 75th percentile: 2.2, 3.6) years, the risk of the primary CV composite was significantly higher with baseline β-blocker use versus no β-blocker use (4.5 vs. 3.4 events/100-patient years, adjusted hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.05–1.29); no significant interaction was noted for patients with versus without prior MI or HF. Baseline β-blocker use was not associated with risks for severe hypoglycemic events (HR 1.14, 95% CI 0.88–1.48). Conclusions: In this observational analysis of T2D and ASCVD, baseline β-blocker use was not associated with risks for severe hypoglycemia yet also was not associated with CV risk reduction over 3 years of follow-up, supporting a randomized examination of chronic β-blocker therapy in this patient population. (TECOS ClinicalTrials.gov number, NCT00790205).