Variables excluded from the models due to the lack of statistical improvement in the model were: ischemic etiology of HF, diabetes mellitus, body mass index, blood systolic pressure, heart rate, atrial fibrillation, chronic obstructive pulmonary disease, hypertension, iron deficiency, cystatin-C, spironolactone/eplerenone treatment, cardiac resynchronization therapy (CRT), and implantable cardiac defibrillator (ICD). This evidence concerns the gene CST3 and chronic obstructive pulmonary disease.