Role of interleukin-6 and insulin resistance as screening markers for metabolic syndrome in patients of chronic obstructive pulmonary disease. A hospital-based cross-sectional study.

Chronic obstructive pulmonary disease (COPD) is usually associated with various extra-pulmonary manifestations. Metabolic syndrome (MetS) is one such entity that has been scarcely studied in Indian patients. The availability of a good screening marker may help in the timely detection of this co-morbidity in COPD patients. We conducted a cross-sectional study to evaluate the prevalence of MetS among COPD patients and the role of Interleukin-6 and insulin resistance (as measured by HOMA-IR) as screening markers for MetS in COPD. One hundred stable COPD patients were evaluated for MetS using US National Cholesterol Education Program Adult Treatment Panel III (2005) guidelines. Interleukin-6 and HOMA-IR (for insulin resistance) were measured and compared between COPD patients with and without MetS. ROC analysis was done to find both the molecules' best cut-off value and sensitivity and specificity in detecting MetS. In the results, the mean age of the study cohort was 59.9±8.7yrs (males=93). Forty-five COPD patients (45%) fulfilled the criteria for MetS. Patients with MetS were comparatively younger (57.9+9.5 v/s 61.6+7.8 years; p=0.037) but had a longer duration of preceding COPD (9.9±2.8 v/s 6.0±2.2 years; p<0.001) as compared to those without MetS. Both IL-6 and HOMA index were statistically higher (p<0.05) in COPD-MetS patients compared to the other group. A cutoff value of 36.3 pg/ml for IL-6 and 1.61 for HOMA index, IL-6 and HOMA-IR had sensitivity of 91.1% and 82.2%, respectively in detecting MetS among COPD patients. To conclude, metabolic syndrome is common comorbidity seen in COPD patients. Interleukin-6 has a better sensitivity than HOMA-IR in screening MetS among COPD patients.