Risk of herpes zoster (shingles) in patients with rheumatoid arthritis under biologic, targeted synthetic and conventional synthetic DMARD treatment: data from the German RABBIT register.

Objective: To compare event and incidence rates of herpes zoster (HZ), also known as shingles, in patients with rheumatoid arthritis under treatment with conventional synthetic (cs), targeted synthetic (ts) or biologic (b) disease-modifying antirheumatic drugs (DMARDs).

Methods: Patients were prospectively enrolled from 2007 until October 2020. Reported HZ events were assigned to ongoing treatments or those terminated within 1 month prior to the HZ event. Exposure-adjusted event rates (EAERs) of HZ were calculated per 1000 patient years (py) and adjusted HRs with 95% CIs computed. Inverse probability weights (IPW) were used to adjust for confounding by indication.

Results: Data of 13 991 patients (62 958 py) were analysed, with 559 HZ events reported in 533 patients. The EAER of HZ was highest for tsDMARDs (21.5, 95% CI 16.4 to 27.9), followed by B cell targeted therapy (10.3, 95% CI 8.0 to 13.0), monoclonal antitumour necrosis factor (anti-TNF) antibodies (9.3, 95% CI 7.7 to 11.2), interleukin 6 inhibitors (8.8, 95% CI 6.9 to 11.0), soluble TNF receptor fusion protein (8.6, 95% CI 6.8 to 10.8), T cell costimulation modulator (8.4, 95% CI 5.9 to 11.8) and csDMARDs (7.1, 95% CI 6.0 to 8.3). Adjusted for age, sex and glucocorticoids and weighted with IPW, tsDMARDs (HR 3.66, 95% CI 2.38 to 5.63), monoclonal anti-TNF antibodies (HR 1.63, 95% CI 1.17 to 2.28) and B cell targeted therapy (HR 1.57, 95% CI 1.03 to 2.40) showed a significantly higher risk compared with csDMARDs.

Conclusion: Our results provide evidence for a 3.6-fold increased risk of HZ associated with tsDMARDs and an increased risk of HZ under bDMARDs compared with csDMARDs.