REN and COVID-19: According to disease severity, the prevalence of disease, hyponatremia has been reported to range from 9.9 to 63.6% in COVID-19 patients.[24–26] The water and sodium balance is regulated by water intake pathways (osmoregulation) and antidiuretic hormone, renin-angiotensin-aldosterone system, and natriuretic hormone pathway (volume regulation).