Association between a type 2 inflammatory disease burden score and outcomes among patients with asthma

Background: Although prevalence of co-existing type 2 inflammatory diseases (cT2) in asthma patients has been reported, limited data exist regarding their impact on asthma outcomes. Objective: To assess the impact of cT2 burden on asthma outcomes and to evaluate patterns of clustering of cT2 in a real-world setting. Methods: From medical records of 4.5 million enrollees in 650 primary care practices in the UK (January 2010–December 2017), patients with ≥1 diagnosis code for asthma at any time pre-index date (date of most recent asthma-related medical encounter) and ≥2 asthma-related prescriptions during the year before index date were categorized into the Global Initiative of Asthma (GINA) guideline severity steps. A cT2 burden score (range 0–9) was assigned based on the total number of co-existing conditions (allergic conjunctivitis, allergic rhinitis, anaphylaxis, eczema/atopic dermatitis, chronic rhinosinusitis, eosinophilic esophagitis, food allergy, nasal polyps, or urticaria) for which patients received a medical diagnosis. Multivariate regression models evaluated associations between cT2 burden score and asthma exacerbations and asthma control. Factor analysis was performed to assess which cT2 comorbidities were correlated and exhibited patterns of clustering. Results: Overall, 245,893 patients with asthma were included (mean [SD] age 44.8 [22.1] years; 43.8% male). Between 55% (GINA step 1) and 60% (GINA step 5) of asthma patients had a medical diagnosis for ≥1 other type2dx. Patients with increased cT2 burden were significantly more likely to experience asthma exacerbations and less likely to achieve asthma control. Conclusion: Asthma patients with a higher cumulative cT2 burden score were more likely to experience worse asthma outcomes than those without any cT2 (burden score of 0).