Burden of Herpes Zoster in Individuals with Chronic Conditions in the Republic of Korea: A Nationwide Population-Based Database Study

Background Chronic conditions (CC) may increase the risk of herpes zoster (HZ) infection, leading to a greater healthcare burden in these individuals compared to those without CCs. It is therefore clinically important to quantify HZ disease burden in individuals with and without CCs, given the rapidly ageing population in the Republic of Korea (ROK). Methods This retrospective cohort study examines the trends in incidence rates (IRs) and incidence rate ratios (IRRs) in individuals with CCs aged ≥18 years using the National Health Insurance Service National Sample Cohort (NHIS-NSC) database from 2010–2019. These patients were stratified by age groups, sex, HZ complications, and CCs. The annual average number of HZ patients, IRs and IRRs were calculated for individuals with and without CCs. Results In total, 729,347 patients with HZ were eligible for the study. HZ IRs were highest in patients with diabetes, followed by chronic obstructive pulmonary disease, chronic kidney disease, asthma, and chronic liver disease, with HZ IRRs following a similar trend. Overall, HZ IRs generally increased with age, typically peaking at 60–64 or 65–69 years and were similar for females and males. HZ IRs were highest among patients without complications, followed by HZ with other, cutaneous, ocular, and neurologic complications across all CCs. For each of the CCs, HZ IRs were consistently higher than that of the non-CC population regardless of sex. Conclusions The findings of this study reiterate the importance of HZ prevention for healthy ageing, especially for CCs populations at increased risk of HZ in the ROK.