Screening of dermatology drugs for aberrant use-patterns: An application of epidemiologic estimates and measures of inequality in drug use

Aims: Dermatology treatments require adherence for safe and effective use. Real-world healthcare databases can reveal drug utilization patterns and uncover inappropriate or unexpected use. This study aimed to analyse dermatology drug utilization patterns using epidemiological and inequality measures, leveraging Danish nationwide registries. It also assessed the feasibility of this method for detecting aberrant drug use. Methods: We formed a 2019 cohort of all patients treated for skin conditions through Danish healthcare registries. We calculated prevalence, incidence rates and treatment duration for dermatological drugs. Inequality in drug utilization was assessed using Lorenz curves, Gini coefficients and other measures. Results: The study encompassed 1 021 255 patients using 94 dermatology drugs. Most usage aligned with ‘expected clinical use’, but we detected inequality, with some drugs having high Gini coefficients and disproportionate consumption by the top percentile of users. Notable findings included potential inappropriate antibiotic use, excessive topical corticosteroid use and unexpected drug use duration. Conclusions: In Denmark, dermatology drugs are used primarily as anticipated, with minimal unexpected patterns. Specific follow-up is required to draw conclusions about inappropriate use. This approach demonstrates broad applicability for screening aberrant drug utilization.