Non-alcoholic fatty liver disease associated with greater herpes zoster risk than alcoholic fatty liver disease

Background Disease-related stress can trigger the occurrence of herpes zoster (HZ). Fatty liver disease (FLD) can have adverse effects on the human body and may induce stress in affected individuals. In this study, we investigated whether FLD is associated with an elevated risk of HZ. Methods For this study, we utilized data from the National Health Insurance Research Database, patients with FLD from 2000 to 2017 were observed (follow-up until 2018). Patients were considered to have FLD if they had at least two outpatient visits or at least one admission record with a diagnostic code of FLD. Patients with FLD were matched 1:1 by age, sex, comorbidities, and index year with control patients. Additionally, the FLD was further categorized into non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) groups. Multivariable Cox proportional hazards model was used to calculate the incidence rate and adjusted hazard ratio (aHR) of HZ for FLD and AFLD and for various age groups, sex and comorbidities. Cumulative incidence curve for HZ was plotted through the Kaplan–Meier method, and p-value was calculated using the log-rank test. Results After 1:1 propensity-score matching, each cohort comprised 62,418 patients. The FLD cohort was further divided into NAFLD and AFLD groups, which respectively comprised 55,709 and 6709 patients. The FLD cohort had a risk of HZ significantly higher than that of the control cohort (aHR = 1.06; p < 0.001). Additionally, the NAFLD group exhibited a significantly higher risk of HZ than did the AFLD group (aHR = 1.22; p < 0.001). Among patients without any comorbidities, those with FLD had a higher risk of HZ than did those without FLD (aHR = 1.14; p < 0.001). Conclusion Patients with FLD are at an increased risk of HZ development. Additionally, NAFLD is associated with a higher risk of HZ than AFLD. Therefore, patients with NAFLD should be informed of their increased risk of HZ.