(013) Epidemiology and Disease Burden of Generalized Pustular Psoriasis – A Retrospective Cohort Study in Finland

Background: Generalized pustular psoriasis (GPP) is a rare, severe neutrophilic disease characterized by eruption of multiple pustules affecting the entire body, as well as systemic symptoms. Understanding of the epidemiology and disease burden are necessary for improving patient outcomes and developing care practices of GPP.

Objectives: The objectives of this study were to assess the prevalence and incidence of GPP, and to compare healthcare resource utilization between patients with GPP and matched controls in Finland.

Methods: This was a nationwide, non-interventional, retrospective study utilizing data from the Finnish health registers.

The base population included all patients with a GPP diagnosis (ICD-10: L40.1) in the Care Register for Health Care maintained by the Finnish Institute for Health and Welfare between 1996–2021. The primary study population included patients with two GPP diagnoses at a dermatology clinic in specialty care. Incident cases had their first GPP diagnosis between 2010–2021, and no prior history of GPP diagnoses.

Two age- and gender-matched comparator populations were formed for the base population: a) A population with psoriasis vulgaris (PV; ICD-10: L40.0); b) A population-based control group without a GPP or PV diagnosis.

The data collection period was from 1996 to 2021. The study outcomes were period and annual prevalence and incidence of GPP, and the annual number of all-cause healthcare contacts and hospitalizations.

Results: The period prevalence of GPP was 4.7 per 100,000 persons for the primary study population and 9.9 for the base population. The annual prevalence increased during the data collection period approximately ~3fold. The overall incidence of GPP was 2.1 per 100,000 persons for the primary study population and 4.2 for the base population. There was no clear trend in changes of GPP incidence over time.

The mean annual number of all-cause healthcare contacts in GPP patients (1.74) was 2-fold higher in comparison with population-based (0.84) and PV controls (0.79). The mean annual number of hospitalizations was 3-fold higher in GPP compared to controls (GPP: 1.15 vs. controls: 0.38), and the length of stays were longer for GPP compared to controls (GPP 11.93 days vs. population-based: 4.51, PV: 3.62).

Conclusions: The annual prevalence of GPP has increased over time, but the estimates of GPP are markedly affected by the definition used. The disease is associated with a significant healthcare burden compared to matched population-based and PV controls, highlighting the need for improved management strategies.