OBJECTIVES: This study aims to estimate the societal economic burden of Generalized Pustular Psoriasis (GPP) in Italy and to assess the health-related quality of life (HRQoL) of GPP patients, thereby filling an existing research gap.

METHODS: A prevalence-based, probabilistic cost-of-illness model was developed, considering all direct healthcare and non-healthcare costs, as well as indirect costs. Data was drawn from primary and secondary sources, including published and grey literature, expert opinion, and socioeconomic questionnaires administered to Italian GPP patients. The Psoriasis Disability Index (PDI) questionnaire was used to collect patient-reported HRQoL. The study employed a bottom-up approach and accounted for the uncertainty surrounding parameters with both deterministic and probabilistic sensitivity analysis.

RESULTS: Our estimates revealed that direct healthcare costs due to GPP range between €15,645-€16,021 per patient/year, direct non-healthcare costs from €49-€69 per patient/year, and indirect costs amount to €9,200 per patient/year. Thus, the annual economic burden per GPP patient in Italy ranges from €24,914 to €25,270, which is higher than the economic burden of plaque psoriasis in Italy (€5,226 for moderate plaque psoriasis and €11,434 for severe plaque psoriasis). The total societal cost of GPP in Italy ranges from €2.94 to €2.98 million per year. Furthermore, data from the PDI questionnaire revealed a substantial degree of perceived disability due to GPP, indicating an impaired quality of life for these patients (mostly on daily activities and personal relationships).

CONCLUSIONS: GPP has a significant economic burden and markedly affects patients' quality of life. The direct and indirect costs associated with GPP, which by far exceed the cost of plaque psoriasis, add an economic argument supporting the need for the disease to be treated as a distinct entity and not just a variant of plaque psoriasis. This recognition could lead to more specific management and policies regarding GPP (as a rare disease), including treatment approval and reimbursement.