Abstract
Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are among the most common respiratory disorders, and their coexistence, termed COPD-OSA Overlap Syndrome (OVS), poses unique diagnostic and therapeutic challenges. OVS affects approximately 1% of adults, yet it’s true prevalence is likely underestimated due to variable diagnostic criteria and under recognition. The combination of chronic airflow limitation, recurrent nocturnal hypoxia, and sleep fragmentation creates a synergistic pathophysiological burden characterized by heightened systemic inflammation, oxidative stress, endothelial dysfunction, and autonomic imbalance. These mechanisms contribute to an increased risk of pulmonary hypertension, right-sided heart failure, arrhythmias, and overall cardiovascular morbidity and mortality compared with either disease alone. Clinically, OVS patients experience more profound nocturnal desaturation, greater daytime hypercapnia, and a higher frequency of exacerbations and hospitalizations. Diagnosis relies on screening tools such as the STOP-Bang or NoSAS questionnaires, with confirmation by polysomnography, though oximetry and capnometry remain valuable alternatives in resource-limited settings. Optimal management integrates aggressive treatment of COPD, lifestyle modification, and positive airway pressure therapy, particularly continuous positive airway pressure, which improves oxygenation, reduces exacerbations, and restores survival rates comparable to those of COPD-only patients. Despite its clinical importance, OVS remains understudied, underscoring the need for standardized diagnostic criteria, multicenter prospective trials, and a phenotype-based approach to guide individualized management and improve outcomes in this high-risk population.