BURDEN OF HERPES ZOSTER IN INDIVIDUALS WITH IMMUNOCOMPROMISED CONDITIONS AND AUTOIMMUNE DISEASES IN SOUTH KOREA: A NATIONWIDE POPULATION-BASED DATABASE STUDY

Abstract

Intro: Individuals with immunocompromised conditions (IC), including autoimmune diseases (AID), are more susceptible to herpes zoster (HZ) and its complications. HZ burden in IC/AID individuals in South Korea has not been fully addressed. This study aimed to estimate HZ incidence rate (IR) and economic burden in IC/AID individuals. Methods: This retrospective cohort study used the nationwide Health Insurance Review and Assessment Service database, containing primary and tertiary care billing information for the national health insurance program, to identify HZ cases from 2016–2020 in South Korea. Inpatient and outpatient HZ cases were identified by ICD-10 code B02.x plus antiviral medication prescriptions within 7 days of diagnosis. Reported HZ incidence was used to calculate annual IRs/1,000 persons by dividing number of HZ cases by total number of IC cases. HZ:non-HZ IC cases were matched 1:3 using age, sex, institution, Charlson comorbidity index, IC and IC prevalence period. HZ-associated all‐cause direct medical costs for IC/AID cases were calculated 12 months from index date. Findings: Among 1,229,948 IC/AID individuals (mean age [years]: 53.7 [SD: 16.4]; 56.2% female), annual HZ IR increased from 2016–2020, averaging 23.4/1,000 persons (95% CI: 22.2–24.6), and was higher in females (26.9 [25.4– 28.3]) than males (19.0 [18.0–19.9]. IR increased from 18–49 years of age (YOA), with a substantial increase after 50 YOA, and was highest in 65–69 YOA. Annual IR was highest in individuals with solid organ transplants (37.1 [35.5–38.8]) and hematologic malignancy (35.5 [31.6–39.3]). Mean all‐cause direct medical costs were higher in IC/AID individuals with HZ (4,094 USD) than without (3,230 USD). Conclusion: IC/AID individuals are at higher risk of HZ than non-IC individuals in South Korea. 1-year medical costs were 27% higher in IC/AID individuals with HZ than without. Findings highlight the need for appropriate HZ prevention measures in IC/AID individuals.