Introduction: Asthma epidemiology reports an estimated global prevalence of about 4.3-8.6% in adults, with vast differences among geographical regions. This study analyses a more significant population of asthma patients (473,737 individuals).
Objectives: To study the prevalence of medical diagnosis of asthma, overall and by age, gender, and disease severity, as well as comorbidities and type 2 biomarkers, and undergo medical treatments of a retrospective population-based asthma cohort from Catalonia (Spain).
Methodology: Individuals with a diagnosis of asthma established by medical records at different healthcare levels (primary, hospital, and emergency) from the Catalan Health System (CHS) were included. Socio-demographic characteristics, prevalence, overall and by age and gender, disease severity, comorbidities, and biomarkers of type-2 inflammation were evaluated, together with appropriate medical treatment.
Results: The overall diagnosed asthma prevalence in the population of Catalonia was 6.3%, where patients mainly had mild asthma (5.3%) and were significantly higher in females (6.8%) than males (5.7%). By age groups, asthma was more prevalent in boys and young men adults; however, being more prevalent in females above the age of 30y. The prevalence of severe asthma was 0.4%, 42.6% had uncontrolled asthma, and a high proportion (84.2%) were under systemic corticosteroid prescription. As expected, SABAs were the most prescribed drug (62.6%), followed by systemic corticosteroids (43.3%). More than half (53.8%) of patients showed type 2 inflammation.
Conclusions: Asthma prevalence in Catalonia is similar to other areas studied in Spain, with a high prevalence in women and of T2 asthma. 

Key words: Asthma, Epidemiological study, Population-based, Prevalence, Severity, Comorbidities, Type 2 biomarkers