OBJECTIVES: To estimate the frequency of moderate to severe atopic dermatitis and measure its demographic and clinical characteristics in a Colombian Health Maintenance Organization (HMO) between 2015 and 2022.

METHODS: This study was a retrospective, descriptive and cohort study of patients with moderate to severe atopic dermatitis from 2015 to 2022. The diagnosis of atopic dermatitis is derived from International Classification of Diseases 10th (codes L20.0, L20.81, L20.82, L20.83, L20.84, L20.89, or L20.9) and the classification from moderate to severe is related to the prescription of advanced therapies (phototherapy, dupilumab, systematic corticosteroid, systematic immunosuppressants, or JAK inhibitor).

RESULTS: A total of 14,668 patients met the inclusion and exclusion criteria, most of them were female (67.3%), adults (76,4%), especially between 18 and 49 years (53.5%), and only 27.3% were first diagnosed by a dermatologist. The most common atopic comorbidities were related to endocrine, nutritional, and metabolic diseases (49.3%) and allergic rhinitis (40.3%). Most patients received systemic immunosuppressants (72.6%) or systemic corticosteroids (25.4%) the remaining patients were treated with dupilumab or phototherapy (2.1%). Median follow-up varied over the observed period, i.e. in 2015 it was 219 days while in 2022 it was 173 days. The yearly cumulative cases were characterized by a downward trend between 2015 and 2020, in 2020 it reached its lowest point, 0.39 per 1,000 persons, and in subsequent years this trend reversed, reaching 0.96 per 1,000 in 2022. This was higher among females, teenagers (12-17 years) and in those with an allergy status (ICD 10^th Z910).

CONCLUSIONS: Patients with moderate to severe atopic dermatitis were working age adults, females and had as main comorbidity an endocrine, nutritional, and metabolic disease. The yearly cumulative frequency had a U-shape behavior during 2015 to 2022 with its lowest point in 2020.