Behavioural patterns in allergic rhinitis medication in Europe: A study using MASK-air real-world data.

Co-medication is common among patients with allergic rhinitis (AR), but its dimension and patterns are unknown. This is particularly relevant since AR is understood differently across European countries, as reflected by rhinitis-related search patterns in Google Trends. This study aims to assess AR co-medication and its regional patterns in Europe, using real-world data. We analysed 2015-2020 MASK-air European data. We compared days under no medication, monotherapy, and co-medication using the visual analogue scale (VAS) levels for overall allergic symptoms ("VAS Global Symptoms") and impact of AR on work. We assessed the monthly use of different medication schemes, performing separate analyses by region (defined geographically or by Google Trends patterns). We estimated the average number of different drugs reported per patient within one year. We analysed 222,024 days (13,122 users), including 63,887 days (28.8%) under monotherapy, and 38,315 (17.3%) under co-medication. The median "VAS Global Symptoms" was 7 for no medication days, 14 for monotherapy and 21 for co-medication (p<0.001). Medication use peaked during the spring, with similar patterns across different European regions (defined geographically or by Google Trends). Oral H -antihistamines were the most common medication in single and co-medication. Each patient reported using an annual average of 2.7 drugs, with 80% reporting two or more. AR medication patterns are similar across European regions. One third of treatment days involved co-medication. These findings suggest that patients treat themselves according to their symptoms (irrespective of how they understand AR), and that co-medication use is driven by symptom severity.