Prevalence, associated factors, and clinical consequences of metabolic syndrome in chronic obstructive pulmonary disease patients: a 5-year prospective observational study

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by multiple systemic comorbidities, not only airflow limitation. Metabolic syndrome (MetS) is a common comorbidity. Patients with COPD have a higher risk of MetS than do healthy individuals. OBJECTIVES: We aimed to investigate the prevalence of and explore the factors associated with MetS in Thai COPD patients and to assess the clinical consequences of MetS after a 5-year follow-up period. METHODS: A prospective observational study was conducted in patients with stable COPD at Songklanagarind Hospital between June 2015 and November 2019. MetS was defined according to the International Diabetes Federation 2005 criteria. The patients were followed-up for 5 years. The prevalence, associated factors, and consequences of MetS were analyzed. RESULTS: A total of 115 patients with COPD were enrolled, of whom 95.3% were male. The overall prevalence of MetS was 37.4% (43 patients). Chronic bronchitis and high C-reactive protein (CRP) levels were independently and significantly associated with MetS in patients with COPD (p = 0.036 and 0.044, respectively). After following patients for 5 years, the incidence of cardiovascular disease and stroke, exacerbation rate, and mortality rate were significantly higher in the COPD with MetS group [relative risk (RR) = 15.36, 95% confidence interval (CI) = (2.13–110.67), RR = 45.43, 95% CI = (4.61–447.07), RR = 1.94, 95% CI = (1.40–2.70), and RR = 48.01, 95% CI = (1.12–2049.43), respectively]. CONCLUSION: The prevalence of MetS is high in patients with COPD. Chronic bronchitis and high CRP levels are associated with MetS in COPD. The incidence of clinical consequences was significantly higher in patients with COPD and MetS after a 5-year follow-up. Screening for MetS is strongly recommended for all patients with COPD.