Patients with PsA Have a Greater Economic Burden for Herpes Zoster

David Singer, PharmD

Credit: LinkedIn

A study shows patients with psoriasis and psoriatic arthritis (PsA) not only have an increased incidence of herpes zoster, but the herpes zoster increases healthcare resource usage and economic burden.¹

“It is our belief that ours is the first study to report on the [healthcare resource use] and costs of [herpes zoster] among patients with PsA,” wrote investigators, led by David Singer, from GSK, the US Health Economics and Outcomes Research in Philadelphia.

Around 20% of patients with psoriasis develop psoriatic arthritis—and psoriatic arthritis puts people at risk of herpes zoster.² However, it was not known how herpes zoster impacts healthcare resource use and costs. Thus, investigators sought to estimate the incidence of herpes zoster among adults with PsA versus those without PsA, as well as the healthcare resource use and costs among patients with PsA with and without herpes zoster.¹

Investigators conducted a retrospective, longitudinal, cohort study by leveraging data from Optum’s de-identified Clinformatics Data Mart (CDM) Database. The team identified 38,113,848 patients from October 1, 2015, to February 28, 2020. Index was defined as the date of the first herpes zoster diagnosis or when participants were randomly assigned to the no herpes zoster group.

The study included 57,126 participants with PsA and 23,837,237 without PsA or psoriasis. Compared to the no cohort, patients with PsA were older (mean age: 57.4 vs 49.7 years), had a greater comorbidity burden (mean CCI, 0.8 vs 0.4), more frequently had a rheumatoid arthritis diagnosis (15.2% vs 0.9%), more often used systemic PsA or psoriasis treatments or phototherapy (64.6% vs 11.5%), and had greater mean all-cause healthcare costs during baseline ($20,711 vs $6102).

Herpes zoster was greater in the group with PsA than without PsA (14.85 vs 7.67 per 1000 person-years; adjusted incidence rate ratio [aIRR], 1.23; 95% confidence interval [CI], 1.16 – 1.30). The finding indicates that for every 1000 patients with psoriatic arthritis observed for 1 year, about 15 will develop herpes zoster.

After adjusting for age groups, patients with PsA still had a greater herpes zoster incidence than patients without PsA. The study also found patients with PsA were 23% more likely to develop herpes zoster than people without PsA.

Participants with PsA and herpes zoster (n = 1045) had 2 – 3 times greater number of outpatient visits, emergency department visits, and inpatient admissions than participants with PsA but no herpes zoster (n = 36,091) during the first month after a herpes zoster 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).

Additionally, mean all-cause per-patient costs were significantly greater in participants with PsA and herpes zoster than participants with PsA and no herpes zoster during the first month after index ($6493 vs $4521, respectively; adjusted cost difference, $2012; 95% confidence interval [CI], $1204 - $3007). The healthcare resource usage and costs were greater in the PsA and herpes zoster cohort during the first 3 and 12 months.

Investigators said the results were limited by using the CDM database, since they did not have participants with insurances outside of commercial and Medicare Advantage with Part D plans, and they did not have data on clinical measures such as disease severity, physician notes, patient-reported outcomes, or quality of life measures.

“Results from this study help to fill a gap in the literature; considering the burden of [herpes zoster] among patients with PsA, the findings are important to understand the impact of [herpes zoster] in this population and could be used to inform clinical decision-making regarding [herpes zoster] prevention,” investigators concluded.

References

1. ^{Singer D, Thompson-Leduc P, Ma S, et al. Burden of Herpes Zoster Among Patients with Psoriatic Arthritis in the United States. Psoriasis (Auckl). 2024;14:63-78. Published 2024 Jun 22. doi:10.2147/PTT.S430151}
2. ^{Alinaghi F, Calov M, Kristensen LE, et al. Prevalence of psoriatic arthritis in patients with psoriasis: a systematic review and meta-analysis of observational and clinical studies. J Am Acad Dermatol. 2019;80(1):251–265.e219. doi:10.1016/j.jaad.2018.06.027}