Metabolic Syndrome Is Associated with Greater Symptom Burden and Comorbidity in Chronic Obstructive Pulmonary Disease: A Secondary Analysis of the Serbian COPD Registry.

Background

Chronic obstructive pulmonary disease (COPD) and cardiovascular diseases (CVDs) are closely linked through shared inflammatory and metabolic pathways. Metabolic syndrome (MetS), shared by both conditions, may represent a key mechanistic link between systemic inflammation, cardiovascular disease, and COPD outcomes.

Objective

To assess the prevalence and clinical correlates of MetS and examine whether increasing MetS burden is linked to more severe symptoms and a higher comorbidity load in patients with COPD.

Methods

We analyzed cross-sectional data from a multicenter COPD registry. MetS was defined by the presence of at least three components: obesity, hypertension, hyperglycemia, or dyslipidemia based on clinical and medication data. Associations between MetS burden and COPD characteristics were evaluated using multivariable models adjusted for age, sex, smoking history, exacerbation status, lung function, inhaled therapy, and study center.

Results

Among 5030 patients, MetS was present in 10.4% and was more frequent in women (11.9% vs. 9.6%, p = 0.01). Patients with MetS had greater symptom burden, and more frequent signs of cyanosis, cor pulmonale, and heart failure. MetS was most common in Global Initiative for Chronic Obstructive Lung Disease stage II-III and associated with higher forced expiratory volume in one second but lower forced vital capacity, with similar exacerbation rates between the groups. Cardiovascular, sleep, renal, and connective tissue comorbidities were more prevalent in patients with MetS. A dose-response relationship was observed, with each additional metabolic syndrome component independently associated with increased odds of respiratory symptoms and cardiometabolic comorbidities (all p < 0.01).

Conclusions

Our findings suggest that metabolic syndrome is present in approximately 10% of patients with COPD and is associated with greater symptom burden and a higher prevalence of cardiovascular, renal, and sleep-related comorbidities. The observed stepwise relationship supports the presence of a clinically relevant cardiometabolic profile in COPD. However, given the cross-sectional registry-based design, causal inferences cannot be made, and prospective studies are needed to confirm these associations and evaluate targeted interventions.