Dapagliflozin, Spironolactone or Both for HFpEF (SOGALDI-PEF)

Inclusion Criteria: Provision of informed consent prior to any study specific procedures HFpEF diagnosis* (irrespective of time from diagnosis) Male or female patients, aged ≥50 years NYHA Class II-IV LVEF ≥45% NT-pro BNP ≥220 pg/mL or BNP ≥80 pg/mL if in sinus rhythm (SR) NT-pro BNP ≥660 pg/mL or BNP ≥240 pg/mL if in atrial fibrillation (AF) Echocardiography with at least one of the following criteria: LAVI ≥29 ml/m2 (≥34 ml/m2 if AF) Lateral E/e' ≥9 LVMI ≥115 g/m2 If male or ≥95 g/m2 if female LV wall thickness ≥12mm eGFR ≥30 ml/min/1.73m2 (CKD-EPI formula) Blood Potassium ≤5.5 mmol/L Not treated with MRAs and/or SGLT2i within the previous month before inclusion and have no history of diabetic ketoacidosis while in treatment with SGLT2 inhibitors Stable/chronic ambulatory patients i.e., patients without need for hospitalization within the last 30 days due to heart failure decompensation episodes If female, she must be a woman of non-childbearing potential. That is, she must be: Surgically sterilized (e.g. underwent hysterectomy, bilateral salpingectomy or bilateral oophorectomy) Clinically diagnosed infertile In a post-menopausal state, defined as no menses for 12 months without an alternative medical cause. A female patient of childbearing potential must have a negative serum pregnancy test at Visit 1 (Day 0) and must agree to consistently and correctly use (from 28 days prior to first study treatment administration until at least 7 days after last study treatment administration) one of the following highly effective methods of contraception: Abstinence of heterosexual intercourse (when this is in line with preferred and usual lifestyle of the subject) Progestogen-only hormonal contraception associated with inhibition of ovulation (oral, injectable, implantable) Combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation (oral, intravaginal, transdermal) Intrauterine device Intrauterine hormone-releasing system Bilateral tubal occlusion Vasectomized partner, who has received medical assessment of the surgical success, or clinically diagnosed infertile partner Exclusion Criteria: Involvement in the planning and/or conduct of the study (applies to both Investigator staff and/or staff at the study site) Participation in another clinical study with an investigational product during the last month Unwilling or unable to sign the informed consent form Surgical procedure, coronary, cerebral or peripheral vascular events or sepsis in the prior 90 days Cancer (life-limiting or less than 2 years in remission) Any previously confirmed autoimmune disease Type 1 Diabetes Severe hepatic impairment (Child-Pugh class C) Ability to walk is, in the investigator's opinion, clearly limited by joint disease or other locomotor problems or lung diseases rather than by cardiorespiratory fitness Previously confirmed cardiac amyloidosis Severe valvulopathy according to the echocardiogram report Patients with a known hypersensitivity or intolerance to spironolactone or dapagliflozin or any of the excipients of the products. Female patients currently pregnant (confirmed by a positive pregnancy test) or intent to become pregnant or breast feeding.