(B-026) Herpes zoster Infection and Its Association with Myocardial Infarction: Insights from a Nationwide Self-Controlled Case Series Study

Background: Herpes zoster (HZ), caused by varicella zoster virus (VZV) reactivation, can lead to various complications affecting quality of life. However, the relationship between HZ and acute myocardial infarction (MI) risk, and the impact of antiviral therapy remains poorly understood.

Objectives: To evaluate the temporal association between HZ and acute MI risk, and assess the impact of antiviral therapy

Methods: Using Taiwan's National Health Insurance database (2017–2020), we conducted a retrospective, population-based study of adults (≥18 years) with incident herpes zoster (HZ) and myocardial infarction (MI) identified from both outpatient and inpatient claims. To ensure diagnostic validity, only patients who had an emergency visit or were hospitalized with a primary diagnosis of MI were certified with the disease, and the date of diagnosis was considered the first day of MI. The index date was defined as the first occurrence of an HZ diagnosis, ascertained from an inpatient or outpatient visit with a primary diagnosis of HZ. By adopting a self-controlled case series (SCCS) design to control for time-invariant confounders, we compared MI incidence across different time periods. The pre-exposure period was defined as the 28 days preceding the HZ diagnosis, while the risk period extended for 12 months after the index date. Conditional Poisson regression was used to calculate incidence ratios (IRs) and 95% confidence intervals (CIs) for MI.

Results: The MI incidence per 100 person-years increased from 25.89 (95% CI: 25.43-26.35) during the reference period to 39.99 (95% CI: 33.86-47.21) in weeks 1-4 post-HZ diagnosis. The adjusted incidence rate ratio (IRR) peaked during weeks 1-4 (1.53, 95% CI: 1.29-1.82). Subgroup analyses showed elevated risks in both antiviral users (IRR: 1.71, 95% CI: 1.36-2.16) and non-users (IRR: 1.36, 95% CI: 1.06-1.76).

Conclusions: HZ is associated with increased MI risk, particularly within the first month post-diagnosis, regardless of antiviral treatment. These findings highlight the importance of cardiovascular monitoring in HZ patients and improving patient outcomes.