After the meta-analysis of above studies, we concluded that hyponatremia is a predictor of heart failure in patients with ACS (RR: 1.71; 95%CI: 1.41–2.07), the potential mechanism may be similar to the influence of hyponatremia on prognosis in patients with congestive heart failure–the release of vasopressin, activation of the renin-angiotensin system and catecholamine production[11, 12]. Here, REN is linked to Hyponatremia.