Comparison of Diagnostic and Therapeutic Protocols for Chronic Obstructive Pulmonary Disease (COPD): Global Initiative for Chronic Obstructive Lung Disease (GOLD) vs. American Thoracic Society/European Respiratory Society (ATS/ERS) Guidelines

Chronic obstructive pulmonary disease (COPD) is a leading cause of global morbidity and mortality. International clinical practice guidelines, specifically the 2025 Global Initiative for Chronic Obstructive Lung Disease (GOLD) and the joint American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines, provide standardized frameworks for its diagnosis and management. This narrative review compares these two frameworks, highlighting the trade-off between GOLD's clinical simplicity and the ATS/ERS emphasis on physiological precision. Key areas of divergence include diagnostic thresholds (fixed ratio vs. lower limit of normal), treatment classification systems (GOLD's ABE tool vs. ATS/ERS phenotype-driven care), and the use of biomarkers like blood eosinophils. Understanding these nuances is critical for clinicians to optimize diagnostic labeling and long-term therapeutic outcomes.