Asthma, COPD, and asthma–COPD overlap: A comparative study of inflammatory biomarkers and quality of life

ABSTRACT Background: Asthma, COPD, and ACO are chronic airway disorders with distinct and overlapping features. This study aimed to compare clinical profiles, inflammatory biomarkers, and quality of life among these groups. Methods: A cross-sectional study was conducted on 168 patients (56 each with asthma, COPD, and ACO). All participants underwent clinical assessment, spirometry, St George’s Respiratory Questionnaire (SGRQ), skin prick testing, and measurement of inflammatory markers, including FeNO, eosinophil count, total IgE, vitamin D, hs-CRP, and interleukins (IL-4, 5, 6, 8, 13, 17, 33). Results: ACO patients were younger than COPD patients but older than asthma patients. Asthma patients had the highest prevalence of allergic rhinitis and skin prick positivity. FEV 1 and FEV 1 /FVC were significantly lower in COPD and ACO compared to asthma, but not different between COPD and ACO. Bronchodilator response was higher in asthma and ACO than in COPD. Asthma patients had significantly higher FeNO, eosinophil counts, and IgE levels compared to COPD, with ACO showing intermediate values. IL-4 and IL-5 were highest in asthma, IL-6 and IL-8 in COPD, with ACO again showing intermediate levels. ACO patients had the highest SGRQ scores, indicating the worst quality of life. Correlation analysis showed group-specific associations between interleukins and clinical parameters. Conclusion: ACO exhibits intermediate clinical and inflammatory profiles between asthma and COPD. While individual biomarkers assist in characterizing these diseases, a combination of clinical, functional, and inflammatory parameters offers better differentiation. ACO patients experience a significant symptom burden, necessitating tailored diagnostic and therapeutic approaches.