Association between ischemic stroke and herpes zoster in older people: a propensity-matched cohort study

Ischemic stroke is known to cause immune dysregulation, yet its potential impact on subsequent herpes zoster risk remains unclear. This study aimed to evaluate whether ischemic stroke was associated with incident herpes zoster among patients aged 65-84 years.

This retrospective cohort study utilized electronic medical records from 2006 to 2024, obtained through the TriNetX Collaborative Network. Two study groups were identified: patients aged 65-84 years with a diagnosis of ischemic stroke, and controls without any cerebrovascular disease diagnosis. We conducted 1:1 propensity score matching, with demographic characteristics, comorbidities, and medication use included as covariates in the propensity score model. The primary outcome was a new diagnosis of herpes zoster. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using the "Compare Outcomes" module within the TriNetX platform.

After 1:1 propensity score matching and applying a post-matching 3-month lag exclusion, 25 011 patients in the ischemic stroke group and 25 029 patients in the control group were included. Over a 5-year follow-up period, the cumulative incidences of herpes zoster were 0.492% in the ischemic stroke group and 0.156% in the control group. In the Cox proportional hazards model, ischemic stroke was significantly associated with an increased risk of incident herpes zoster (HR, 3.607; 95% CI, 2.515-5.173), although the absolute incidence was low.

Ischemic stroke is associated with a higher risk of herpes zoster in patients aged 65-84 years. Further studies are warranted to clarify the underlying mechanisms and potential clinical implications. Key messages What is already known on this topic  The risk of herpes zoster increases with aging and immune senescence.Ischemic stroke can induce central nervous system injury-related immune suppression, thereby increasing susceptibility to infections. What this study adds  The Cox model demonstrated an association between ischemic stroke and incident herpes zoster, although the absolute incidence was low during follow-up. How this study might affect research, practice, or policy  Among patients aged 65-84 years, ischemic stroke is associated with a higher cumulative incidence of herpes zoster.Clinicians should remain attentive to the possibility of herpes zoster in post-stroke care, particularly in older people.