Metabolic syndrome in chronic obstructive pulmonary disease: paradoxical relationships between systemic inflammation, oxygenation, and lipid profiles with implications for one-year clinical outcomes

Abstract

Background
Chronic obstructive pulmonary disease (COPD) was recognized as a systemic disorder frequently accompanied by metabolic comorbidities, including metabolic syndrome (MS). The coexistence of COPD and MS was thought to amplify systemic inflammation, alter metabolic and lipid profiles, and adversely affect clinical outcomes. However, the prevalence of MS in COPD and its prognostic impact on mortality and exacerbations had not been fully defined. This study aimed to estimate the prevalence of metabolic syndrome among patients with COPD and to examine its association with one-year mortality and exacerbation outcomes, as well as its interplay with systemic inflammation, oxygenation status, and lipid profile parameters.


Methods
A prospective follow-up study included 184 patients with confirmed COPD. Baseline demographic, clinical, and laboratory data, including inflammatory markers, lipid profile, and metabolic parameters, were collected at enrollment. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, requiring at least three of the following: central obesity, elevated triglycerides, reduced HDL cholesterol, elevated blood pressure, or elevated fasting glucose (or corresponding treatment). Patients were followed for one year to document mortality and COPD exacerbations. Multivariable logistic regression analyses were performed to identify predictors of mortality and exacerbation.


Results

Metabolic syndrome was identified in 23.9% of the COPD cohort. Patients with MS were significantly older and experienced more frequent exacerbations, greater oral corticosteroid use, and higher utilization of home oxygen therapy. During the one-year follow-up period, overall mortality was 44.6%, and 68.5% of patients experienced at least one exacerbation. COPD patients with MS had significantly higher one-year mortality (
p
 = 0.02) and exacerbation rates (
p
 = 0.001) compared with those without MS. Increasing age, elevated C-reactive protein, and diabetes mellitus independently predicted mortality, whereas smoking, elevated inflammatory markers, low HDL-C, and lower hemoglobin levels predicted exacerbations. Inverse correlations were observed between inflammatory markers and total cholesterol and LDL, while oxygen saturation was positively associated with lipid levels. Triglyceride levels were positively correlated with HbA1c.



Conclusion
Metabolic syndrome was common among patients with COPD and was associated with worse clinical outcomes, including increased mortality and exacerbations. The observed paradoxical relationships between inflammation, oxygenation, and lipid profiles highlighted the complex systemic nature of COPD and underscored the importance of comprehensive metabolic and inflammatory assessment to improve risk stratification and management.