Generalized Pustular Psoriasis Burden in Taiwan: Claims Study

Key Takeaways

• Recurrent flares were recorded in 99.2% of the GPP cohort, and recurrent flare event rates were higher than in matched PV.
• Higher all-cause outpatient, emergency, and inpatient use was observed in GPP, with the largest relative gap seen for severe recurrent flares and inpatient care.
• Median total costs were higher during the 12-week post-index period and across full follow-up, and outpatient services accounted for the largest early cost share.

According to a nationwide claims analysis of 245 patients in Taiwan with generalized pustular psoriasis who had an incident flare, recurrent flares were nearly universal and median monthly costs were about twice those in matched psoriasis vulgaris. Healthcare use was also higher across outpatient, emergency, and inpatient settings after flare onset and over follow-up.

Investigators used Taiwan’s National Health Insurance Research Database in a nationwide retrospective cohort covering claims from 2016 through 2020. Patients with GPP identified by ICD-10-CM L40.1, treated with systemic therapy, and with no prior PV were required to have an incident flare between January 1, 2017, and September 30, 2020. Up to 4 propensity-matched PV comparators identified by ICD-10-CM L40.0 were selected for each case, yielding 967 matched PV patients. The GPP cohort had a mean age of 51.3 years, and 49.8% were male. Hypertension, diabetes, dyslipidemia, and thyroid disease were common comorbidities.

During follow-up, 1,156 moderate-to-severe flares were recorded, and recurrence was near universal among patients with GPP. Among patients with recurrence, median follow-up was 2.9 years in GPP and 2.7 years in PV. In the recurrence-restricted analysis, overall recurrent flare event rates were higher in GPP, with a rate ratio of 1.14 and a 95% CI of 1.06 to 1.23. The moderate recurrent flare rate ratio was 1.09, with a 95% CI of 1.01 to 1.18, and the severe recurrent flare rate ratio was 2.82, with a 95% CI of 2.01 to 3.95, the widest relative separation from PV.

At 12 weeks, ER, OPD, and IPD IRRs were 1.43, 1.11, and 1.92, with CIs of 1.04 to 1.97, 1.05 to 1.17, and 1.46 to 2.51. Across full follow-up, ER, OPD, and IPD IRRs were 1.33, 1.03, and 1.69, with CIs of 1.19 to 1.49, 1.01 to 1.05, and 1.50 to 1.91. Median total cost at 12 weeks was USD 579.70 in GPP versus USD 274.40 in PV, and outpatient services accounted for the largest early cost share. Over full follow-up, median monthly costs were USD 187.10 versus USD 92.60, while outpatient cost ratios were 1.40 at 12 weeks and 1.31 overall.

The analysis measured all-cause healthcare utilization and costs, so spending could not be assigned specifically to GPP-related care. Flare severity was inferred from treatment escalation and care setting because claims data did not include GPPASI, GPPGA, or PASI scores. The study period spanned 2016 through 2020.