Assessment of Exhaled Volatile Organic Compounds (VOCs) in Smokers vs. Non-Smokers for the Early Detection of Chronic Obstructive Pulmonary Disease (COPD)

Chronic Obstructive Pulmonary Disease (COPD) is a major global health concern, and early diagnosis is important to improve outcome. Volatile organic compounds (VOCs) analysis in the exhaled breath has been a much-promoted, non-invasive method under review. The objective of this study was to determine whether exhaled VOCs are useful as biomarkers for the early diagnosis of COPD by evaluating VOC profiles in COPD and normal controls with various smoking statuses (non-smokers, ex-smokers, and active smokers). In a case-control study with 84 patients with COPD and 84 age- and gender-matched healthy controls who were stratified by smoking status, exhaled breath samples were analyzed using GC-MS for VOC identification and quantitation. Quantitative results were expressed as mean ± SD and analyzed with independent t-tests, chi-square tests, Pearson correlations, logistic regression, and ROC curve analysis. COPD patients had higher concentrations of some hydrocarbons and aldehydes (e.g., hexane, ethane) than controls (p < 0.001). VOC levels were higher in active smokers compared to non-smokers and ex-smokers. VOC levels correlated positively with the level of smoking intensity (r = 0.68, p < 0.001). ROC analysis revealed that a few VOCs were highly diagnostic in terms of detecting early COPD (AUC > 0.85). In Conclusion, VOC profiling during exhalation can discriminate patients with COPD from healthy subjects and provides insight into the metabolic impact of smoking. Such findings justify the incorporation of VOC analysis as a diagnostic and screening tool for the assessment of early COPD detection and monitoring. The future will aim to translate these biomarkers into larger, longer-term cohorts.