In fact, a further association exists between SGLT2i and a reduced risk of hyperkalemia, a very frequent complication in HF patients that is closely related to comorbidities (i.e., chronic kidney disease and diabetes mellitus), as well as to HF therapy (such as the renin–angiotensin–aldosterone system (RAAS) inhibitors) [23]. The gene discussed is REN; the disease is hydrops fetalis.