Objective: To estimate the incidence of herpes zoster (HZ) in patients with rheumatoid arthritis (RA) compared with the general population in the USA.
Methods: This retrospective, longitudinal cohort study used data from an administrative claims database containing both commercial and Medicare Advantage Part D data, with a data period from October 2015 to February 2020. Patients were aged ≥ 18 years and divided into 2 cohorts: patients with RA and patients without RA. Diagnosis and procedure codes were used to identify HZ cases and calculate incidence rates (IRs) of HZ in the 2 cohorts. Data were stratified by age group (ie, 18-49, 18-29, 30-39, 40-49, 50-64, and ≥ 65 yrs) and RA therapy type. IR ratios (IRRs), adjusted by cohort baseline characteristics, were estimated using generalized linear models to compare the incidence of HZ between cohorts.
Results: The overall IR of HZ was higher in the RA cohort (21.5 per 1000 person-years [PY]; N = 67,650) than in the non-RA cohort (7.6 per 1000 PY; N = 11,401,743). The highest IRs in both cohorts were observed in the age group of ≥ 65 yrs (23.4 and 11.4 per 1000 PY in the RA cohort and non-RA cohort, respectively). The overall adjusted IRR of HZ was 1.93 (95% CI 1.87-1.99, P < 0.001) for the RA cohort compared with the non-RA cohort. In the RA cohort, the highest IRs by medication class were observed in patients using corticosteroids and those using Janus kinase inhibitors.
Conclusion: These results highlight the increased incidence of HZ in patients with RA.
Keywords: United States; adult; herpes zoster; incidence; rheumatoid arthritis.
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