Risk of Herpes Zoster in Patients with Adhesive Capsulitis of the Shoulder

Background: Physical diseases, such as infection, and emotional distress are associated with herpes zoster (HZ). However, the relationship between adhesive capsulitis of the shoulder (ACoS) and HZ remains unknown. Objective: This study investigated the risk of HZ development in patients with ACoS. Methods: We analyzed the Longitudinal Health Insurance Database, a subset of 1 million beneficiaries from the National Health Insurance Research Database. Patients newly diagnosed with ACoS during the 2000–2012 period were the case group. Each patient with ACoS was matched to a control, according to age and index year, through frequency matching. HZ was the primary event in this study. Results: A total of 60,478 patients were included and each group contained 30,239 patients. The risk of HZ infection in the case cohort was 1.28 times that of the control cohort. ACoS increased the risk of HZ infection in each age group, particularly among patients aged younger than 50 [adjusted hazard ratio (aHR) = 1.52, 95% confidence interval (CI): 1.31–1.75]. Relative to the control group, the hazard ratio of HZ for male patients (aHR = 1.40, 95% CI: 1.26–1.55) in the case group was higher than that for female patients (aHR = 1.22, 95% CI: 1.13–1.32). Conclusion: Patients with ACoS have a higher risk of HZ development, particularly among those aged younger than 50 years. The effect of ACoS on HZ development among young adults requires attention.