ACE and Hyperkalemia: Another factor that may influence the prognosis of patients with HFrEF and concomitant CKD, especially in those with glomerular filtration rate < 30 mL/min/1.73 m2, is that these patients are less likely to receive the specific therapies that reduce mortality in HFrEF, such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, ARNI, SGLT-2 inhibitors, and mineralocorticoid antagonists, because of kidney dysfunction and hyperkalemia.