Incidence and Clinical Characteristics of Herpes Zoster in Patients With Spondyloarthritis Receiving Biologic Therapy: A 36-Month Multicenter Registry-Based Study

Objectives: Herpes zoster, caused by the reactivation of varicella-zoster virus, has been reported in patients with autoimmune inflammatory diseases receiving biologic therapies. However, data regarding its occurrence in patients with spondyloarthritis (SpA) remain limited. This study aimed to determine the incidence of herpes zoster and describe the clinical characteristics of affected patients with SpA receiving biologic therapy. Methods: A multicenter retrospective registry-based study was conducted over a 36-month period, including patients with SpA receiving biologic therapy and registered in the Moroccan Society of Rheumatology Biotherapy Registry (BRMSR). Clinical, laboratory data, including erythrocyte sedimentation rate and C-reactive protein, and therapeutic data were collected at baseline, at 36 months, and at the time of herpes zoster infection. A descriptive statistical analysis was performed. Results: A total of 194 patients with SpA were included, with a mean age of 40.23 ± 13.68 years. The cohort included 123 males (63.4%) and 71 females (36.6%), with a mean disease duration of 11 ± 7 years. Most patients (98.5%) were treated with anti-tumor necrosis factor agents, with etanercept being the most commonly prescribed biologic therapy. The incidence of herpes zoster was 6.87 cases per 1,000 person-years (95% CI: 2.018-16.85). Four cases of herpes zoster were identified. These patients were all older than 55 years, had associated comorbidities, and had prolonged exposure to biologic therapy. Conclusions: The incidence of herpes zoster in patients with SpA receiving biologic therapy was low. The four reported cases shared common clinical characteristics, including older age, the presence of comorbidities, and prolonged exposure to biologic therapy. Further studies with larger populations and longer follow-up are needed to better characterize herpes zoster occurrence in this population.