Prevalence of Cardiovascular Diseases in COPD-OSA Overlap Syndrome Versus COPD Alone: A Systematic Review.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is frequently associated with cardiovascular comorbidities. Obstructive sleep apnea (OSA) may coexist with COPD, forming the so-called overlap syndrome (OS), and may further increase cardiovascular risk through intermittent hypoxia, systemic inflammation, and sympathetic activation. This systematic review is aimed at synthesizing and comparing the burden of cardiovascular comorbidities in patients with COPD and coexisting OSA versus those with COPD alone, thereby identifying the additional cardiovascular burden associated with OSA and gaps in current knowledge. MATERIALS AND METHODS: A systematic search was conducted in PubMed and Web of Science from inception to 3rd of January 2026, using predefined search terms related to COPD, OSA, and cardiovascular diseases. Only observational studies in adults were included. RESULTS: Nineteen studies were included in the final analysis. Most studies had a cross-sectional or retrospective cohort design. Cardiovascular disease was reported as a baseline characteristic in nearly all included studies; however, none evaluated the prevalence of cardiovascular disease as a primary outcome; these conditions were reported mainly as associated comorbidities. Overall, most included studies reported a higher prevalence of cardiovascular diseases-particularly systemic arterial hypertension-in patients with overlap syndrome compared with COPD alone, frequently reaching statistical significance; however, this finding derived from unadjusted comparisons of baseline comorbidities, and no study adjusted for confounders such as age, body mass index, or smoking. CONCLUSIONS: Although many of the observed differences were statistically significant, they derived from unadjusted comparisons of baseline characteristics, which limits the ability to draw firm conclusions regarding causality. Future studies including larger populations of patients with COPD and OSA are required to accurately determine the prevalence of cardiovascular disease and better describe the relationship between COPD, OSA, and cardiovascular comorbidities.