https://orcid.org/0000-0001-8008-8003
Figures & data
Figure 1 Study designs for the assessment of (A) HZ incidence (PsA+ and PsO–/PsA– cohorts) and (B) HRU and costs (PsA+/HZ+ and PsA+/HZ– cohorts).
Notes: aBased on the distribution of the pre-index eligibility (ie, time between beginning of continuous enrollment and index date) in the PsA+/HZ+ cohort. bPatients had to have ≥1 claim associated with a PsA diagnosis during 12-month baseline.
Abbreviations: HRU, healthcare resource use; HZ, herpes zoster; PsA, psoriatic arthritis; PsA+, patients with psoriatic arthritis; PsA+/HZ+, patients with psoriatic arthritis and herpes zoster; PsA+/HZ–, patients with psoriatic arthritis but without herpes zoster; PsO–/PsA–, patients with neither psoriatic arthritis nor psoriasis.
Table 1 Demographic Characteristics at Index
Table 2 Baseline Clinical Characteristics
Figure 2 Unadjusted incidence rates and aIRRs of HZ in the PsA+ vs PsO–/PsA– cohorts, aOverall and by age at index.
Notes: aThe mean ± SD observation period in the PsA+ cohort was 20.2 ± 14.4 months (18.4 ± 14.0, 19.4 ± 14.3, 22.6 ± 14.7 months across age groups); in the PsO–/PsA– cohort 20.9 ± 15.7 months (18.2 ± 14.8, 20.2 ± 15.4, 26.8 ± 16.0 months across age groups). baIRRs were calculated using the PROC GENMOD procedure for GLMs assuming a Poisson distribution and log link, accounting for the propensity score of being diagnosed with PsA and relevant baseline characteristics. The GLM for the overall cohort adjusted for propensity score based on the following baseline characteristics: index year, age at index, sex, race, region, insurance type, CCI, any comorbidity associated with HZ, additional immunosuppressive conditions, use of specific PsO/PsA treatment type, inpatient costs, outpatient costs, ED costs, other medical costs, and pharmacy costs, as well as the same characteristics excluding sex (doubly robust adjustment). For the age stratifications, age at index was excluded from the propensity score and doubly robust adjustment by design.
Abbreviations: aIRR, adjusted incidence rate ratio; CCI, Charlson Comorbidity Index; CI, confidence interval; ED, emergency department; GLM, generalized linear model; HZ, herpes zoster; PsA, psoriatic arthritis; PsA+, patients with psoriatic arthritis; PsO, psoriasis; PsO–/PsA–, patients with neither psoriatic arthritis nor psoriasis; PY, person-years; SD, standard deviation.
Figure 3 HRU in the PsA+/HZ+ vs PsA+/HZ– cohorts during the first 1, 3, and 12 months after index.
Notes: aHRU encounters were calculated as the average number of HRU events per patient during the period of interest. baIRRs were calculated using the PROC GENMOD procedure for GLMs assuming a negative binomial distribution and log link, accounting for the propensity score of being in the PsA+/HZ+ cohort (for the PsA+/HZ– cohort) and relevant baseline characteristics. The GLM adjusted for a propensity score based on the following baseline characteristics: index year, age at index, sex, race, region, insurance type, having only one PsO or PsA diagnosis prior to index, CCI, any comorbidity associated with HZ, additional immunosuppressive conditions, use of specific PsO/PsA treatment type, inpatient costs, outpatient costs, ED costs, other medical costs, and pharmacy costs, as well as the following characteristics (doubly robust adjustment): age at index, inpatient costs, outpatient costs, ED costs, other medical costs, and pharmacy costs.
Abbreviations: aIRR, adjusted incidence rate ratio; CCI, Charlson Comorbidity Index; CI, confidence interval; ED, emergency department; GLM, generalized linear model; HRU, healthcare resource use; HZ, herpes zoster; PsA, psoriatic arthritis; PsA+/HZ+, patients with psoriatic arthritis and herpes zoster; PsA+/HZ–, patients with psoriatic arthritis but without herpes zoster; PsO, psoriasis.
Figure 4 All-cause mean per-patient costs in the PsA+/HZ+ vs PsA+/HZ– cohorts during the first (A) 1 month, (B) 3 months, and (C) 12 months after index.
Notes: aIncluding skilled nursing facilities, home care services, hospice, vision care, and durable medical equipment. bAdjusted cost differences were estimated using the two-part modeling approach: (1) the probability of observing a positive cost was modeled using logistic regression; (2) a GLM with a gamma distribution and log link was used to predict costs among patients with positive costs. Both models included the patients’ propensity scores and relevant baseline characteristics. The 95% CIs were estimated from nonparametric bootstrap procedures with 499 replications. The GLM adjusted for a propensity score based on the following baseline characteristics: index year, age at index, sex, race, region, insurance type, having only one PsO or PsA diagnosis prior to index, CCI, any comorbidity associated with HZ, additional immunosuppressive conditions, use of specific PsO/PsA treatment type, inpatient costs, outpatient costs, ED costs, other medical costs, and pharmacy costs, as well as the following characteristics (doubly robust adjustment): age at index, insurance type, inpatient costs, outpatient costs, ED costs, other medical costs, and pharmacy costs.
Abbreviations: CCI, Charlson Comorbidity Index; CI, confidence interval; ED, emergency department; GLM, generalized linear model; HZ, herpes zoster; PsA, psoriatic arthritis; PsA+/HZ+, patients with psoriatic arthritis and herpes zoster; PsA+/HZ–, patients with psoriatic arthritis but without herpes zoster; PsO, psoriasis; SD, standard deviation; USD, United States Dollars.
Figure 5 HZ-related mean per-patient medical costs in the PsA+/HZ+ cohort during the first 1, 3, and 12 months after index.
Notes: aIncluding skilled nursing facilities, home care services, hospice, vision care, and durable medical equipment.
Abbreviations: ED, emergency department; HZ, herpes zoster; PsA+/HZ+, patients with psoriatic arthritis and herpes zoster; SD, standard deviation; USD, United States Dollars.
Data Sharing Statement
The data that support the findings of this study are available from Optum, but restrictions apply to the availability of these data, which were used under license for the current study and so are not publicly available.