Importance of hypochloremia in patients with acute heart failure: should decongestive therapy be tailored based on...

Serum chloride has recently emerged as a potential prognostic biomarker in heart failure (HF), with hypochloremia linked to poor outcomes and diuretic resistance. We aimed to evaluate the prevalence, predictors, and prognostic significance of hypochloremia at admission in ADHF patients.

We conducted a retrospective cohort study including 638 patients admitted with ADHF between 2016 and 2025 at a tertiary hospital. Baseline clinical, laboratory, and ultrasound data were collected within the first 48 h. Hypochloremia was defined as serum chloride <96 mmol/L at admission. The primary endpoint was a composite of all-cause mortality (ACM) and/or HF rehospitalization at 180 days. Cox regression analyses were performed to identify independent predictors.

Hypochloremia was present in 15.7% of patients. This group had higher rates of chronic HF, greater outpatient loop diuretic use and doses, lower sodium and diastolic blood pressure, and higher bicarbonate levels. Independent predictors of hypochloremia included lower sodium levels, inferior vena cava enlargement, and lower creatinine. At 180 days, the primary endpoint occurred more frequently in the hypochloremic group. Admission hypochloremia independently predicted the composite outcome (HR 2.68; 95% CI 1.27-5.67; p = 0.010), along with higher outpatient loop diuretic doses and lower admission sodium.

Hypochloremia on admission is independently associated with worse outcomes in patients hospitalized for ADHF. Serum chloride is an accessible, low-cost marker that may help identify high-risk patients and provide additional insight into congestion status. Further prospective studies are needed to confirm its prognostic role and determine whether chloride-guided approaches can improve clinical outcomes.