High incidence of herpes zoster among SLE patients in Indonesia: a retrospective cohort study

OBJECTIVE: Systemic lupus erythematosus (SLE) is associated with increased susceptibility to infections, including herpes zoster (HZ), due to the immune dysregulation experienced and frequent use of immunosuppressive therapy. Data on HZ incidence and risk factors in SLE patients from Southeast Asia remain limited. This study determines the incidence and clinical risk factors of HZ among adult patients with SLE in a tertiary referral centre in Indonesia. METHODS: A retrospective cohort study was conducted among adult SLE patients with at least 6 months of follow-up. Participants were recruited through systematic random sampling from an allergy-immunology outpatient clinic and followed for a total of 733 person-years (median 5.6 years). HZ history was assessed via structured interviews aided by clinical photographs and subsequently confirmed by medical records. The incidence rate was calculated per 1000 person-years. Bivariate and multivariate binomial regression analyses were used to identify independent predictors. RESULTS: A total of 130 patients were enrolled, with one patient declining. The cumulative incidence of HZ was 16.5% (21/130 patients), with an incidence rate of 28.7 per 1000 person-years. Multivariate analysis identified disease duration of ≤1 year (RR: 3.23; 95% CI 1.58 to 6.63; p=0.001) and mycophenolate use (RR: 3.23; 95% CI 1.18 to 8.87; p=0.023) as independent risk factors. Other variables, including corticosteroid dose and comorbidities, were not found to be significantly associated with HZ. CONCLUSION: The incidence of HZ in this Southeast Asian SLE cohort was high, particularly in patients with recent diagnoses and those receiving mycophenolate. These findings highlight subgroups of patients who may be at increased risk and underscore the need for further prospective studies to better define causal pathways and inform preventive strategies in settings with limited access to zoster vaccination.