Abstract 13457: Renin-Angiotensin System Inhibitor Exerts Prognostic Effect in HFpEF Patients With Low Chloride Level

Background: Hypochloremia is associated with a poor prognosis of heart failure (HF) patients. Serum chloride level is known to be affected by serum renin secretion; however, this relationship is one of the least investigated field in HF patients. Renin-angiotensin system inhibitor (RASi) is recommended as a first-line medication for HF patients with reduced left ventricular ejection fraction (LVEF), but its prognostic effect is still controversial in HF patients with preserved EF (HFpEF). Hypothesis: The prognostic benefit of RASi depends on the baseline serum chloride level in HFpEF patients. Methods: This observational study included 1,913 consecutive patients who admitted to hospital due to worsening of HF and discharged alive. After excluding patients who received regular hemodialysis and those whose LVEF <50%, 506 HFpEF patients were ultimately analyzed. They were divided into two groups by serum chloride levels at admission (Low-Chloride group: -101 mEq/L; High-Chloride group: 102- mEq/L), referred to prior reports. Death from any cause as the primary endpoint was compared between patients who received RASi at discharge and those who did not, in each chloride group. Results: During the observation period with 479 days of median follow-up, 77 (15%) died. Patients who received RASi had significantly lower mortality than those who did not, only in the Low-Chloride group (Log-rank: p=0.001, Figure ). In the multivariate Cox regression analysis with diverse covariates, the rate of risk reduction by RASi for the mortality was greater in patients in the Low-Chloride group than High-Chloride group (HR: 0.35 and 0.71, respectively). The prognostic advantages of RASi were evident in patients with low chloride level, but not in those with high chloride level at admission (P for interaction=0.027). Conclusion: In this observational study, the administration of RASi was associated with an improved prognosis of HFpEF patients only in low serum chloride level at admission.