Anti-herpetic Medications and Reduced Risk of Dementia in Patients with Herpes Simplex Virus Infections—a Nationwide, Population-Based Cohort Study in Taiwan

This retrospective cohort study is to investigate the association
between herpes simplex virus (HSV) infections and dementia, and the
effects of anti-herpetic medications on the risk involved, using
Taiwan’s National Health Insurance Research Database (NHIRD). We
enrolled a total of 33,448 subjects, and identified 8362 with newly
diagnosed HSV infections and 25,086 randomly selected sex- and
age-matched controls without HSV infections in a ratio of 1:3, selected
from January 1, to December 31, 2000. A multivariable Cox proportional
hazards regression model was used to evaluate the risk of developing
dementia in the HSV cohort. This analysis revealed an adjusted hazard
ratio of 2.564 (95% CI: 2.351-2.795, P < 0.001)
for the development of dementia in the HSV-infected cohort relative to
the non-HSV cohort. Thus, patients with HSV infections may have a
2.56-fold increased risk of developing dementia. A risk reduction of
dementia development in patients affected by HSV infections was found
upon treatment with anti-herpetic medications (adjusted HR = 0.092 [95%
CI 0.079-0.108], P < 0.001).
Theusage of anti-herpetic medications in the treatment of HSV infections
was associated with a decreased risk of dementia. These findings could
be a signal to clinicians caring for patients with HSV infections.
Further research is, therefore, necessary to explore the underlying
mechanism(s) of these associations.