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.