GSTM1 and anemia: HFpEF is defined as an association of comorbidities, consequently, we have observed the presence of 11 comorbidities in the studied population: obesity, hypertension, hyperlipidemia, DM, history of stroke, CAD, AF, CKD, COPD or asthma, obstructive sleep apnoea, and anemia (defined as Hb level < 13 g/dL in men, <12 g/dL in women).