Clinical and Economic Burden of Herpes Zoster in Patients with Rheumatoid Arthritis: A Retrospective Cohort Study Using Administrative Claims.

Objective: To estimate the incremental healthcare resource utilization (HRU) and cost burden posed by herpes zoster (HZ) in adult patients with rheumatoid arthritis (RA) in the United States.

Methods: A retrospective cohort study was conducted using an administrative claims database containing commercial and Medicare Advantage with Part D data, between October 2015 and February 2020. Patients with RA and HZ (RA+/HZ+) or RA without HZ (RA+/HZ-) were identified based on diagnosis codes and relevant medications. Outcomes measured included HRU and medical, pharmacy, and total costs at month 1, quarter 1, and year 1 after the index date (HZ diagnosis for RA+/HZ+ cohort, randomly assigned for RA+/HZ- cohort). Generalized linear models incorporating propensity scores and other covariates were used to estimate differences in outcomes between cohorts.

Results: A total of 1866 patients from the RA+/HZ+ cohort and 38,846 patients from the RA+/HZ- cohort were included. Hospitalizations and emergency department visits occurred more frequently in the RA+/HZ+ than the RA+/HZ- cohort, especially in the month after HZ diagnosis (adjusted incidence rate ratio [95% confidence interval (CI)] for hospitalizations: 3.4 [2.8; 4.2]; emergency department visits: 3.7 [3.0; 4.4]). Total costs were also higher in the month after HZ diagnosis (mean adjusted cost difference [95% CI]: $3404 [$2089; $4779]), with cost differences driven by increased medical costs ($2677 [$1692; $3670]).

Conclusions: These findings highlight the high economic burden of HZ among individuals with RA in the United States. Strategies to reduce the risk of HZ in patients with RA (such as vaccination) may serve to reduce this burden. Video abstract.