ACE and heart failure: A very high proportion of patients in our study were using angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, thiazide diuretics and furosemide, which is in line with other studies in the literature, which show that these drugs predispose patients to hyponatremia [35,36]; however, for some drugs, such as furosemide, this association may not reflect a causal role with hyponatremia but a causal role between the indication for which the medication is prescribed (more typically heart failure) and hyponatremia.