ASTHMA PHENOTYPES AND COMORBID DISEASES

BACKGROUND: Asthma is a heterogeneous chronic airway disease frequently accompanied by comorbidities that influence symptom burden, treatment requirements, and disease control. Understanding the distribution of comorbidities across asthma phenotypes is essential for improving individualized management strategies. METHODS: This cross-sectional study analyzed data from 2,053 adults enrolled in the nationwide Turkish Asthma Action and Research (TAAR) registry. Demographic characteristics, asthma phenotypes, comorbidities, treatment steps, and control status were extracted. Comorbidities were categorized as upper airway, lower airway, non-respiratory, and psychophysiological disorders. Comparative analyses were performed across phenotypes (eosinophilic, allergic, NERD, obese asthma), treatment steps, and control groups using appropriate statistical tests. RESULTS: Allergic rhinitis (64.2%), chronic rhinosinusitis (32.1%), gastroesophageal reflux (GER) (26.4%), and nasal polyposis (19.9%) were the most frequent comorbidities. Upper airway diseases were significantly more common in eosinophilic asthma, NERD, and allergic asthma. Obesity-related comorbidities-including diabetes mellitus, hypertension, cardiovascular disease, and obstructive sleep apnea -were markedly higher in the obese asthma phenotype and among women. GER was particularly prevalent in NERD, obese asthma, and uncontrolled asthma. Patients in GINA step 5 had the highest comorbidity burden. Poorly controlled asthma was associated with higher frequencies of chronic rhinosinusitis, diabetes mellitus, GER, recurrent URTIs, and osteoporosis. The proportion of uncontrolled asthma increased significantly with rising numbers of comorbidities. CONCLUSION: Comorbidities are highly prevalent among adults with asthma and vary substantially across phenotypes, sex, treatment step, and control status. Upper airway disease, GER, obesity-related conditions, and metabolic disorders exert a major impact on asthma severity and control. Systematic identification and targeted management of comorbidities should be prioritized to optimize asthma outcomes and reduce disease burden.