Temporal changes of hospital contacts due to Herpes zoster during three decades in Denmark

Background Herpes Zoster (HZ) is a common disease associated with morbidity, including cardiovascular complications, particularly in older adults and immunocompromised individuals.Objective To explore temporal changes in the incidence of hospital contacts due to HZ and estimate the risk of stroke and myocardial infarction (MI) following a hospital contact due to HZ.Methods This nationwide register-based cohort study from 1994 to 2022, included all adults (≥ 18 years) living in Denmark with a hospital contact due to a first-time event of HZ registered in the national patient register as an ICD-10 code. The incidences of hospital contact due to HZ were estimated by Poisson regression and reported per 100,000 person-years (PY). Furthermore, we estimated the hazard ratio (HR) of MI or stroke up to 90 days following a hospital contact with HZ using a Cox proportional hazard model.Results We included 23,433 individuals with a hospital contact due to HZ. The incidence of HZ increased in all age groups during the period, with the highest increase in the 60–64 age group from 10 (95% CI: 8–13) to 30 (95% CI: 26–33) per 100,000 PY. The HR of a stroke or MI after a hospital contact with an HZ diagnosis was 2.65 (95% CI: 2.06–3.42, p < 0.001).Conclusion We found that the incidence of hospital contacts with an HZ diagnosis increased during the past three decades. Also, the relative rate of cardiovascular events was higher after a hospital contact with an HZ diagnosis than in individuals without such an event.