Chronic Urticaria: A Swedish Registry-based Cohort Study on Population, Comorbidities and Treatment Characteristics

Abstract

Swedish databases present unique opportunities to research population data on diseases and treatments. The current study is, to our knowledge, the most comprehensive registry-based study on a chronic urticaria population in Sweden to date. The aim of this study was to describe the chronic urticaria population in Stockholm County regarding epidemiology, demographics, comorbidity, healthcare usage and treatment patterns in relation to current international guidelines. Real-world data were extracted between 2013 and 2019, yielding 10,642 adult patients. Study period prevalence of chronic urticaria was 0.53%, the mean annual incidence was approximately 0.08%, and 68% of patients were female. Regarding diagnosis, 58% were first diagnosed in primary care, approximately 50% were diagnosed before the age of 40 years. Regarding type of urticaria, 89% had chronic spontaneous urticaria, 11% had chronic inducible urticaria, and 5% of patients with chronic urticaria had coexisting angioedema. Common coexisting diagnoses were, for example, asthma, allergy, psychiatric and behavioural disorders and cardiometabolic disorders. Treatment patterns generally followed guidelines, yet data indicated that guidelines were not fully implemented, especially in primary care.

Fig. 1

Persistency of chronic urticaria diagnosis (either primary or secondary) in patients who received their first diagnosis in 2014 (n = 1,594), presented as remaining share of total (%) at defined time-periods 3–6 months, 6–12 months, 1–2 years, 2–3 years, 3–4 years and 4–5 years.

Fig. 2

Percentage of patients with chronic inducible urticaria (CINDU), divided by subtype (n = 1,207). Share of total CINDU (%).

Fig. 3

Prescription of systemic glucocorticoids in chronic urticaria population, divided by healthcare provider (n = 5,349). Population limited to first diagnosis of urticaria in July 2013 to December 2018 and to patients receiving glucocorticoids within 1 month after first diagnosis.