RETN and chronic obstructive pulmonary disease: They found that OS patients had higher levels of fasting glucose, fasting insulin, glycated hemoglobin (HbA1c), total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), leptin, resistin, and adiponectin compared to COPD-only patients, whereas high-density lipoprotein cholesterol (HDL-C) was significantly lower in the OS groups [26,35].