Topical drug treatment of rosacea in Switzerland: A descriptive study using Swiss claims data.

Abstract

Introduction: Rosacea, a chronic inflammatory condition primarily affecting the skin of the face, has long been an area of interest for pharmaceutical advancements. In Switzerland, metronidazole was the only first-line topical rosacea medication (TRM), until brimonidine was licensed in 2014 and ivermectin in 2016. We aimed to evaluate the use of TRM between 2012 and 2023 in Switzerland.

Methods: We used claims data from the Swiss health insurance 'Helsana Group' between 2012 and 2023 (study period). We quantified monthly number of claims for each TRM per 10,000 insured persons, as well as overall and annual prevalence of patients treated with TRM in Switzerland, stratified by age (≥/<50 y) and sex in 2023. Among all continuously enrolled persons (period prevalence) and persons insured during the entire calendar year (annual prevalence), we identified all persons with at least one claim of either topical metronidazole, brimonidine, or ivermectin. We additionally evaluated the proportion of patients with only one, two to five, or more than five claims for any TRM during the study period, and stratified patients by number of different TRM claimed within the same calendar year. Lastly, we evaluated the proportion of patients with comedications of interest (i.e. class 1 or 2 topical corticosteroids or oral tetracycline-antibiotics) within the same calendar year.

Results: Metronidazole was the most frequently claimed TRM in Switzerland during the study period (5.1 claims / 10,000 / month) but decreased by 11% since market introduction of ivermectin in 2016. Ivermectin continuously increased, accounting for 43% of all TRM claims in 2023 (4.0 claims / 10,000 / month). Overall prevalence of patients treated with TRM was 4.7%, whereas annual prevalence was lower but increased from 0.4% (2012) to 0.7% (2023); it was highest among women ≥50 years of age (1.4%). Of all patients treated with TRM, 54% had only one claim for any TRM, while 36% had between two and five claims, mostly monotherapy of metronidazole (52%) or ivermectin (36%). Throughout the study period, approximately 7% had at least one claim for any topical corticosteroid within the same calendar year. In total, 16% claimed oral tetracycline-antibiotics (80% doxycycline), which slightly decreased since 2017.

Conclusion: The discrepancy between annual and overall prevalence suggests that many patients treated with TRM receive intermittent therapy. Despite the decline in use, metronidazole remains the most frequently used TRM in Switzerland, but use of ivermectin increased continuously. The slight decrease in tetracycline-antibiotics among patients treated with TRM after 2017 might reflect efficacy of ivermectin.