Risk factors for herpes zoster in patients with systemic lupus erythematosus

International guidelines state that all immunocompromised adults should be vaccinated with the recombinant varicella zoster virus (VZV) vaccine. We aimed to assess the risk factors for herpes zoster (HZ) in patients with systemic lupus erythematosus (SLE).

Electronic medical records of all SLE patients registered at our referral centre were analysed at the time of clinical visit between July and December 2024. Demographic, medical history, laboratory and treatment data were extracted using a standardised data collection form. Herpes zoster incidence and associated factors were identified.

A total of 224 SLE patients (female 93.8 %, median age 48 [38;56] years) were included. Of these, 30 (n = 30/224, 13.4 %) had HZ. The incidence was 0.81 for 100 patient-years. Univariable analysis showed that gamma globulin level (OR 0.81, 95 %CI 0.70-0.92), duration of steroid treatment (OR 1.07, 95 % CI 1.03-1.11), immunosuppressive (IS) drugs (OR 2.41, 95 % CI 1.06-6.05), duration of IS treatment (OR 1.05, 95 % CI 1.00-1.09) and biologics (OR 3.50, 95 % CI 1.53-7.93) were significantly associated with HZ. In a multivariable logistic regression analysis, only gamma globulin level (OR 0.86, 95 % CI 0.74-0.98) remained independently associated with HZ. The ROC curve for gamma globulin levels showed significant associations with HZ (AUC = 0.71 (0.59-0.82)), with a threshold of 10.3 g/L providing the best discrimination between SLE patients with and without HZ.

A reduced level gammaglobulin - with a cut-off of 10.3 g/L - is associated with HZ in SLE and may identify SLE patients who should be prioritized for VZV vaccination.