Generalized pustular psoriasis: A nationwide population-based study using the National Health Data System in France

BackgroundGPP is a rare, chronic, neutrophilic skin disease, with limited real-world data characterizing patients with flares and the impact of flares on disease progression and morbidity.ObjectiveDescribe the clinical characteristics of patients with GPP, comorbidities, disease epidemiology and frequency and severity of flares, and compare patients with GPP with a matched severe psoriasis population.MethodsIn this population-based real-world cohort study an algorithm was developed to identify patients with GPP flares. Three cohorts were identified using the Systeme National des Donnees de Sante (SNDS) database covering almost the entire French population; a prevalent cohort (2010-2018), an incident cohort (2012-2015). A severe psoriasis cohort was compared with the GPP incident cohort using propensity score matching.ResultsThe prevalent and incident cohorts comprised 4195 and 1842 patients, respectively. In both cohorts, mean age was 58 years; 53% were male. Comorbidities were significantly more common in the incident cohort versus matched psoriasis cohort, respectively, including hypertension (44% vs. 26%), ischaemic heart disease (26% vs. 18%) and hyperlipidaemia (25% vs. 15%). In the incident cohort, the flare rate was 0.1 flares/person-year and 0.4 flares/person-year among the 569 out of 1842 patients hospitalized with flares. These patients had a mean (+/- SD) stay of 11.6 +/- 10.4 days; 25% were admitted to the intensive care unit. In 2017, the cumulative incidence and cumulative GPP age-sex standardized prevalence were 7.1 and 45.2 per million, respectively.ConclusionsPatients with GPP had a distinct comorbidity profile compared to patients with severe psoriasis, and GPP flares were associated with long hospitalizations.