Clinical phenotypes of atopy and asthma in COPD: a meta-analysis of SPIROMICS and COPDGene.

Abstract Background Little is known about the concordance of atopy with asthma COPD overlap (ACO). Among individuals with COPD, a better understanding of the phenotypes characterized by asthma overlap and atopy is needed to better target therapies. Research Question What is the overlap between atopy and asthma status among individuals with COPD, and how are categories defined by the presence of atopy and asthma status associated with clinical and radiologic phenotypes and outcomes in the SPIROMICS and COPDGene studies? Study Design and Methods 403 individuals with COPD from SPIROMICS and 696 individuals from COPDGene with data about specific IgEs to 10 common allergens and mixes (simultaneous assessment of combination of allergens in similar category) were included. Comparison groups were defined by atopic and asthma status (neither, atopy alone, atopic asthma, non-atopic asthma, with atopy defined as any positive specific IgE ( > 0.35 KU/L) to any of the 10 allergens or mixes and asthma defined as self-report of doctor diagnosed current asthma). Multivariable regression analyses (linear, logistic, and zero inflated negative binomial where appropriate) adjusted for age, gender, race, lung function, smoking status, pack-years smoked and use of inhaled corticosteroids were utilized to determine characteristics of groups and relationship with outcomes (exacerbations, clinical outcomes, CT metrics) separately in COPDGene and SPIROMICS, and then adjusted results were combined using meta-analysis. Results The prevalence of atopy was 35% and 36% in COPD subjects from SPIROMICS and COPDGene, respectively, and there was less than 50% overlap between atopic status with asthma in both cohorts. In meta-analysis, individuals with non-atopic asthma had the most impaired symptom scores (effect size for St. George’s Respiratory Questionnaire total score, SGRQ, 4.2, 95% CI 0.4 to 7.9; effect size for COPD Assessment Test, CAT, score 2.8, 95% CI 0.089 to 5.4), highest risk for exacerbations (incidence rate ratio 1.41, 95% CI 1.05 to 1.88) compared to the group without atopy or asthma. Those with atopy and atopic asthma were not at increased risk for adverse outcomes. Interpretation Asthma and atopy had incomplete overlap among former and current smokers with COPD in COPDGene and SPIROMICS. Non-atopic asthma was associated with adverse outcomes and exacerbation risk in COPD, while groups having atopy alone and atopic asthma had less risk.