The most important predictive factors for COPD diagnosis were lung function tests (ie, FEV1/FVC, percent vital capacity [%VC], and %FEV1) and smoking status, followed by cough, hematological indices (ie, MCV, MCHC, MCH, Hb, and HT), treatment with antidiabetic drugs, hemoglobin A1c, serum albumin, total protein, and BMI. The gene discussed is GSTM1; the disease is chronic obstructive pulmonary disease.