Individuals with diabetes currently taking β-blockers may have a higher mortality risk compared with individuals without diabetes, including a subset of individuals with diabetes and coronary heart disease (CHD), according to a study published in the Mayo Clinic Proceedings.
Investigators conducted a prospective cohort study, selecting a nationally representative sample of the adult population, which included 2840 individuals with diabetes (697 taking β-blockers; 2143 not taking β-blockers) and 14,684 individuals without diabetes (1584 taking β-blockers; 13,100 not taking β-blockers).
Individuals taking β-blockers had a higher incidence of CHD compared with those not taking β-blockers (P < .001). There were no differences in baseline characteristics of individuals with or without diabetes. The purpose of the study was to assess the relationship and all-cause mortality in individuals taking β-blockers with and without diabetes.
Study results found all-cause mortality to be significantly higher in individuals with diabetes taking β-blockers, with rates at 40.6 per 1000 person-years compared with 17.1 per 1000 patient-years in those not taking β-blockers (adjusted hazard ratio [HR], 1.49; 95% CI, 1.09-2.04; P =.01).
In comparison, individuals without diabetes currently taking and not taking β-blockers had all-cause mortality rates of 13.8 and 5.9 per 1000 patient-years, respectively. The unadjusted HR comparing individuals with diabetes taking and not taking β-blockers was 2.51 (95% CI, 1.90-3.34; P <.001). There was no significant difference in the HR of individuals without diabetes who were taking or not taking β-blockers (adjusted HR, 0.99; 95% CI, 0.79-1.25; P =.96).
When results were further investigated comparing β1-selective and specific β-blockers, all-cause mortality was also found to be higher in both drug groups when compared with individuals not taking β-blockers (adjusted HR, 1.60 [95% CI, 1.13-2.24; P =.007] and adjusted HR, 1.55 [95% CI 1.09-2.21; P =.01], respectively).
Individuals with CHD taking and not taking β-blockers were found to have an all-cause mortality of 56.6 and 32.7 per 1000 person-years, respectively, compared with individuals without diabetes who were found to have all-cause mortality rates of 20.5 and 26.3 per 1000 person-years, respectively. Individuals with both CHD and diabetes taking β-blockers were found to have a higher all-cause mortality rate when compared with individuals not taking β-blockers (adjusted HR, 1.64; 95% CI, 1.08-2.48; P =.02). The HR was lower in individuals with CHD taking β-blockers not diagnosed with diabetes (adjusted HR, 0.68; 95% CI, 0.50-0.94; P =.02).
In individuals with a history of a myocardial infarction, there was a significantly higher all-cause mortality in individuals with diabetes currently taking β-blockers compared with those not taking a β-blocker (adjusted HR, 2.24; 95% CI, 1.24-4.07; P =.008), whereas the mortality of individuals without diabetes was found to be significantly lower in individuals currently taking β-blockers (adjusted HR, 0.59; 95% CI, 0.38-0.93; P =.02).
The researchers concluded that “[f]urther studies are needed to assess whether β-blockers are effective in reducing mortality and coronary events in diabetic patients receiving optimal medical treatment.”
Tsujimoto T, Kajio H, Shaprio MF, Sugiyama T. Risk of all-cause mortality in diabetic patients taking β-blockers. Mayo Clin Proc. 2018;93:409-418.