The following is a summary of “Incidence of Herpes Zoster in Patients With Rheumatoid Arthritis in the United States: A Retrospective Cohort Study,” published in the July 2023 issue of Rheumatology by Singer et al.

This study aims to determine the incidence of herpes zoster (HZ) in patients with rheumatoid arthritis (RA) relative to the general population in the United States. This retrospective, longitudinal cohort analysis utilized data from an administrative claims database that included commercial and Medicare Advantage Part D data from October 2015 to February 2020. Patients ≥ 18 years old were divided into two cohorts: those with RA and those without RA. 

Using diagnosis and procedure codes, HZ cases were identified, and incidence rates (IRs) of HZ in the two cohorts were calculated. Data were stratified by age group (i.e., 18-49, 18-29, 30-39, 40-49, 50-64, and 65 years) and type of RA therapy. Using generalized linear models, IR ratios (IRRs) adjusted by cohort baseline characteristics were estimated to compare the incidence of HZ between cohorts. The incidence rate (IR) of HZ was higher in the RA cohort (21,5 per 1000 person-years; N = 67,650) compared to the non-RA cohort (7.6 per 1000 person-years; N = 11,401,743). In both cohorts, the maximum incidence rates were observed in individuals aged ≥ 65 (23,4 and 11,4 per 1000 person-years in the RA and non-RA cohorts, respectively). 

The aggregate adjusted IRR of HZ for the RA cohort was 1.93 (95% CI 1.87-1.99, P<0.001) compared to the non-RA cohort. In the cohort of patients with rheumatoid arthritis, corticosteroids, and Janus kinase inhibitors were associated with the highest IRs by medication class. These findings emphasize the increased prevalence of HZ in RA patients.

Source: jrheum.org/content/50/7/873