β-Blocker therapy postmyocardial infarction is generally recommended because it reduces mortality. However, β-blockers may increase anaphylaxis mortality in the growing population of patients with peanut-induced anaphylaxis.

We sought to assess the risks and benefits of β-blocker therapy among patients with peanut allergy and heart disease.

We created a Markov model for patients with heart disease at risk for peanut-induced anaphylaxis to compare life expectancy with the following strategies: (1) β-blocker and (2) no β-blocker. Meta-analysis and a literature review were used to estimate model parameters. We performed sensitivity analysis to explore parameter uncertainty.

For peanut-allergic patients who are postmyocardial infarction or who have congestive heart failure, the heart disease benefit of β-blockers outweighs the increased likelihood of dying from anaphylaxis, increasing life expectancy by 9.4 and 17.4 months, respectively. β-Blocker was preferred unless (1) the annual rate of moderate to severe anaphylaxis exceeded 6.0% for postmyocardial infarction and 15% for congestive heart failure patients; (2) β-blocker therapy increased the incidence of moderate to severe anaphylaxis >2.5-fold for postmyocardial infarction and >5.8-fold for congestive heart failure patients; (3) anaphylaxis case fatality exceeded 6.5% postmyocardial infarction; or (4) β-blocker therapy increased anaphylaxis case fatality >25-fold postmyocardial infarction.

Our results suggest that for patients postmyocardial infarction or with congestive heart failure who are at risk for peanut-induced anaphylaxis, β-blocker use should still improve survival. However, the epidemiology of anaphylaxis and effects of β-blocker therapy on anaphylaxis incidence and mortality require further study.