Risk of herpes zoster in patients with rheumatoid arthritis in the biologics era from 2011 to 2015 and its association with methotrexate, biologics, and corticosteroids

Objectives To elucidate the incidence and risk factors of herpes zoster (HZ) in patients with rheumatoid arthritis (RA) in the biologics era. Methods We determined the rate of HZ occurrence among the RA patients that participated in the Institute of Rheumatology, Rheumatoid Arthritis surveys from 2011 to 2015, by assessing medical records. The standardised incidence rate per 1000 patient-years with a 95% confidence interval (CI) was calculated, and risk factors for HZ were analysed using a time-dependent Cox regression analysis. Results Among 7815 patients (female, 84.7%) contributing to 25,863 patient-years of observation, 340 HZ events in 309 patients were confirmed. The standardised incidence rate (95% CI) per 1000 patient-years was 8.5 (6.9-10.5) in total, 6.0 (3.7-9.2) in men, and 11.0 (8.7-13.7) in women. Risk factors for HZ were age per 10 years (hazard ratio 1.14, 95% CI 1.03-1.26, p < .05), Japanese version of the Health Assessment Questionnaire (J-HAQ) score of 0.5-1.5 (versus J-HAQ = 0; 1.51, 1.09-2.10, p < .05), methotrexate use (1.58, 1.06-2.36, p < .05), and biologic use (1.88, 1.44-2.47, p < .01). Conclusions In the era when biologics were frequently used and corticosteroid use and doses were decreasing, methotrexate and biologics increased the risk for HZ.