BACKGROUND: Recent evidence suggests that medications not primarily targeting the cardiovascular (CV) system may have cardioprotective effects in patients with heart failure (HF), in particular the anti-diabetic therapies sodium-glucose co-transporter-2 (SGLT-2) antagonists and glucagon-like peptide-1 (GLP-1) agonists. We conducted a systematic review to assess the pooled evidence for the use of SGLT-2 antagonists and GLP-1 agonists in patients with HF and the effect of biological sex on the results. METHODS: MEDLINE, Embase, Cochrane Library and clinical trial databases were searched until February 2023. Randomized controlled trials (RCTs) published in English that included adult participants with HF who were randomized to an SGLT-2 antagonist or GLP-1 agonist with a primary or secondary outcome of HF hospitalization (HFH) or CV death were eligible for inclusion. Data pooling was undertaken using a random effects model and odds ratios (ORs) to determine the association between drug and outcome. Sub-group analyses to investigate sex differences were conducted. RESULTS: Six RCTs were included (24 781 patients). Four studies investigated SGLT-2 antagonists, and two studies examined GLP-1 agonists. SGLT-2 antagonists improved HFH {OR [95% confidence interval (CI)]: 0.69 [0.63, 0.77], P < 0.001} and CV death [0.87 (0.78, 0.97), P = 0.01] independent of diabetes status, with excellent homogeneity across all four studies. No beneficial effects were found for GLP-1 agonists. The effects of SGLT-2 antagonists on HFH and CV death were similar in men and women [OR (95% CI): HFH, 0.70 (0.64, 0.76), P < 0.001 and 0.58 (0.46, 0.74), P < 0.001, respectively; CV death, 0.86 (0.78, 0.95), P = 0.003 and 0.84 (0.73, 0.96), P = 0.01, respectively], and the neutral effect of GLP-1 agonists on HFH and CV death was similar in men and women (all P > 0.05). CONCLUSIONS: SGLT-2 antagonists but not GLP-1 agonists beneficially affect HFH and CV death in patients with HF with or without diabetes. We show for the first time that GLP-1 agonists have a neutral effect on HFH and CV death in both male and female HF patients and a reduction in HFH and CV death in male and female HF patients taking SGLT-2 antagonists.