Burden of Herpes Zoster Among Patients with Psoriatic Arthritis in the United States.

Purpose: Patients with psoriasis (PsO) and psoriatic arthritis (PsA) are at increased risk of herpes zoster (HZ), but healthcare resource use (HRU) and costs relating to HZ in adults with PsA are unknown. We aimed to estimate the incidence of HZ among adults with PsA vs without psoriatic disease and the additional HRU and costs among patients with PsA with vs without HZ.

Patients and methods: This retrospective, longitudinal, cohort study estimated HZ incidence in PsA+ vs PsO-/PsA- cohorts and HRU and medical/pharmacy costs among PsA+/HZ+ vs PsA+/HZ- cohorts comprised of adults from Optum's de-identified Clinformatics Data Mart Database during 2015-2020. For the HRU/cost analyses, index was the date of first HZ diagnosis (PsA+/HZ+ cohort) or was randomly assigned (PsA+/HZ- cohort). Generalized linear models were used for adjusted comparisons between cohorts.

Results: HZ incidence was higher in the PsA+ (n = 57,126) vs PsO-/PsA- (n = 23,837,237) cohort (14.85 vs 7.67 per 1000 person-years; adjusted incidence rate ratio [aIRR]: 1.23; 95% confidence interval [CI]: 1.16-1.30). Numbers of outpatient visits, emergency department visits, and inpatient admissions were significantly higher in the PsA+/HZ+ (n = 1045) vs PsA+/HZ- (n = 36,091) cohorts during the first month after HZ diagnosis (outpatient: aIRR: 1.74; 95% CI: 1.63-1.86; emergency department: 3.14; 95% CI: 2.46-4.02; inpatient: aIRR: 2.61; 95% CI: 1.89-3.61). Mean all-cause per-patient costs were significantly higher in the PsA+/HZ+ vs PsA+/HZ- cohorts during the first month after index ($6493 vs $4521; adjusted cost difference: $2012; 95% CI: $1204-$3007). HRU and costs were numerically higher in the PsA+/HZ+ cohort during the first 3 and 12 months.

Conclusion: These findings, which provide evidence on the increased incidence and HRU and economic burden associated with HZ among adults with PsA, could be used to inform clinical practice and decision-making.