(C-048) Global Assessment of the Diagnosed Prevalence of Psoriasis and Plaque Psoriasis

Background: Psoriasis (PsO) is a common, chronic, immune-mediated inflammatory skin disease with multiple comorbidities. The heterogeneity in disease definitions, patient identification methods and PsO types have contributed to the wide variations in prevalence estimates of PsO in the published literature.

Objectives: To evaluate the prevalence of PsO worldwide and quantify global, regional and country-specific 12-month prevalence estimates for diagnosed overall PsO and plaque PsO.

Methods: A comprehensive literature search was conducted to identify population-based studies reporting the prevalence of PsO. Keywords were used to search MEDLINE, Web of Science Core Collection and SciELO, without language restrictions, for articles published between 2013 and 2023. Diagnosed prevalent cases of PsO were defined as individuals with a diagnosis of PsO made by a physician via medical records, clinical examinations or self-report, or identified with International Classification of Diseases diagnosis codes. For countries lacking country-specific estimates, proxy countries were selected based on similarities in race/ethnicity, geographic proximity and gross domestic product per capita to extrapolate prevalence. For all countries assessed, diagnosed prevalent cases were calculated by multiplying the annualized age- and sex-specific diagnosed prevalence with the corresponding age- and sex-specific population estimates from the United Nations World Population Prospects (2019). Prevalence estimates over a 10-year projection period were also calculated.

Results: Out of 9,633 identified publications, 85 met the inclusion criteria. The global estimate of diagnosed overall PsO, spanning 71 geographies in total and across all ages, was 0.81% in 2024. Regionally, diagnosed PsO prevalence estimates ranged from 2.26% in the US and 2.56% in Europe (including France, Germany, Italy, Spain, UK) to 0.33% in Japan and 0.35% in China. For diagnosed plaque PsO, the global estimate was 0.69%, with regional estimates of 2.01% for the US, 2.10% for Europe, 0.29% for Japan and 0.32% for China. Across all countries, the diagnosed prevalence of PsO and plaque PsO in adults ranged from 0.11% to 5.25% and 0.09% to 4.27%, respectively, and in children from 0.01% to 1.33% and 0.01% to 1.03%, respectively. Global estimates of diagnosed PsO increased modestly over the 10-year projection period (from 0.81% in 2024 to 0.83% in 2033), with variations observed across regions.

Conclusions: The 2024 global diagnosed prevalence estimate of PsO is approximately 1% with higher rates in the US and Europe versus China and Japan. PsO was less common in children than in adults. The slight increase in global prevalence over time is partially attributed to changes in age and sex compositions over time.