Prevalence of Atopic Dermatitis in the adult population of Catalonia (Spain): a retrospective, large-scale population-based study.

BACKGROUND AND OBJECTIVES: Studies on the prevalence of Atopic Dermatitis (AD) for the adult cohort in general-based populations are scarce worldwide. We performed a retrospective population-based observational cohort study of 537,098 adult patients diagnosed with AD in Catalonia (Spain), a larger population than in previous studies. To study the prevalence of AD generally by age, gender, disease severity, multi-morbidities, and serum total Immunoglobin E (tIgE) and undergo appropriate medical treatment (AMT) for the Catalan population.

METHODS: Adult individuals (≥18 years old) diagnosed with AD by medical records at different health care levels (primary, hospital, emergency) from the Catalan Health System (CHS) were included. Statistical analyses were conducted to evaluate socio-demographic characteristics, prevalence, multi-morbidities, serum tIgE and AMT.

RESULTS: The overall diagnosed AD prevalence in the adult Catalan population was 8.7%, being higher for the non-severe (8.5%) than for the severe (0.2%) populations and females (10.1%) than males (7.3%). Topical corticosteroids were the most prescribed drug (66.5%), and the use of all prescribed treatments was higher in severe AD patients, especially systemic corticosteroids (63.8%) and immunosuppressant agents (60.7%). More than half (52.2%) of severe AD patients reported serum tIgE ≥ 100 KU/L, and higher values were observed for those with multi-morbidities. Acute bronchitis (13.7%), allergic rhinitis (12.1%), and asthma (8.6%) were the most frequent comorbid respiratory diseases.

CONCLUSIONS: Our study provides new and robust evidence of AD´s prevalence and related characteristics in adults using a large-scale population-based study and a more significant cohort of individuals.