Abstract
BACKGROUND: The aim of this cohort study was to investigate the association between hyperthyroidism and the likelihood of developing herpes zoster in Taiwan. METHODS: Using the National Health Insurance Research Database (NHIRD) in Taiwan, we selected individuals aged 20-84 who were newly diagnosed with hyperthyroidism between 2013 and 2020 as the hyperthyroidism group. These individuals were then matched with a control group without hyperthyroidism in a 1:1 propensity score matching for sex, age, and baseline comorbidities. The occurrence of herpes zoster was tracked in both groups until the end of the study period or until a diagnosis of herpes zoster was made. The Cox proportional hazards regression analysis was used to determine the hazard ratio (HR) and 95 % confidence interval (CI) for the risk of herpes zoster associated with hyperthyroidism. RESULTS: A total of 202,069 individuals with hyperthyroidism and 202,069 individuals without hyperthyroidism were included in the analysis. The incidence rate of herpes zoster was higher in the hyperthyroidism group compared to the non-hyperthyroidism group (6.10 per 1000 person-years for the hyperthyroidism group versus 5.53 per 1000 person-years for the non-hyperthyroidism group, incidence rate ratio = 1.10, 95 %CI = 1.07-1.14, and P value < 0.001). After adjusting for covariables, individuals with hyperthyroidism were found to have a higher risk of developing herpes zoster compared to those in the non-hyperthyroidism group (adjusted HR = 1.19, 95 %CI = 1.15-1.23, and P < 0.001). CONCLUSION: This cohort study suggests that individuals with hyperthyroidism in Taiwan may have a greater risk of developing herpes zoster compared to those without hyperthyroidism.