Role of interluekin-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 a variety of extra-pulmonary manifestations. Metabolic syndrome (MetS) is one such entity that has been scarcely studied in Indian patients. Availability of a good screening marker may help in 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 to evaluate the role of Interleukin-6 and insulin resistance (as measured by HOMA-IR) as screening markers for MetS in COPD. A total of 100 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 the best cut-off value and sensitivity and specificity of both the molecules in detecting MetS. In the results, the mean age of the study cohort was 59.9 +/- 8.7 years (males=93). Forty five COPD patients (45%) fulfilled the cri-teria for MetS. Patients with MetS were comparatively younger (57.9 +/- 9.5 vs 61.6 +/- 7.8 years; p=0.037) but had longer duration of preceding COPD (9.9 +/- 2.8 vs 6.0 +/- 2.2 years; p<0.001) as compared to those without MetS. Both IL-6 and HOMA index were statisti-cally higher (p<0.05) in COPD-MetS patients as compared to the other group. At cutoff value of 36.3 pg/ml for IL-6 and 1.61 for HOMA index, IL-6 and HOMA-IR had sensitivity 91.1% and 82.2% respectively in detecting MetS among COPD patients. To conclude, metabolic syndrome is a common comorbidity seen in COPD patients. Interleukin-6 has a better sensitivity than HOMA-IR in screening MetS among COPD patients.