The risk of laryngitis with herpes zoster infection: A nested case-control study using data from the Korean National Sample Cohort.

<h4>Background</h4>Whether herpes zoster infection (HZI) affects laryngitis incidence remains unknown.<h4>Objective</h4>The purpose of this population-based retrospective study was to analyze the relationship between laryngitis and HZI using data from the Korean Health Insurance Review and Assessment Service-National Sample Cohort.<h4>Methods</h4>This study analyzed 1,197,093 medical claim codes from 2018. Patients with HZI (ICD-10: B02) were retrospectively identified. Laryngeal diseases were defined by ICD-10 codes for five subgroups: 1) malignant disease, 2) benign disease, 3) vocal cord palsy, 4) inflammatory disease, and 5) reflux disease.<h4>Results</h4>Among the Korean population older than 20 years, 12,809 experienced HZI. Subjects with HZI were more likely to be older (mean age: 51.54 years vs. 48.06 years, p <0.0001). The proportion of subjects with laryngeal disease was higher in those with HZI than in those without HZI (55.55% vs. 41.37%, p <0.0001). Laryngeal disease was significantly associated with HZI in multiple regression analysis (odds ratio (OR) = 1.77, 95% confidence interval: 1.71-1.84) after adjusting for age, sex, hypertension, diabetes, dyslipidemia, ischemic heart disease, cerebral stroke, and depression. Among laryngeal disease subgroups, inflammatory disease (OR = 1.05; 95% CI: 1.01-1.09) and reflux (OR = 1.20; 95% CI: 1.15-1.25) were associated with HZI.<h4>Conclusions</h4>HZI is independently associated with laryngitis. Results of this study have implications for etiological investigations and prevention strategies for laryngitis.