Evaluating Hyponatremia as a Predictor of Mortality in Heart Failure Patients in a Tertiary Healthcare Setting

Background Heart failure (HF) is a condition that has a high morbimortality, with high levels of hospitalization and death in most countries. Hyponatremia is a frequent electrolyte imbalance in HF and can indicate neurohormonal release and disease severity. This study determined the effects of admission hyponatremia on in-hospital and 30-day mortality in hospitalized HF patients. Methodology In this prospective cohort study, 220 patients with HF admitted to a tertiary cardiology unit from September to December 2023 were enrolled. Patients were classified into hyponatremic (<135 mmol/L), mild (130-134 mmol/L), moderate-to-severe (<130 mmol/L), and normonatremic (≥135-145mmol/L). The severity of HF was determined as left ventricular ejection fraction (LVEF <40%, 40-49%, and ≥50%). Demographics, comorbidities, renal function, and medications were documented. Independent t-tests and chi-square tests were used for statistical analysis, with p-values <0.05 considered significant. Cox regression models were used to assess mortality outcomes after adjusting for renal function and diuretic class. Results Hyponatremia was found in 92 (41.8%) patients, more common in cases with low LVEF. Higher in-hospital mortality (17 (18.5%) vs 9 (7.0%), p = 0.011), 30-day mortality (23 (25.0%) vs. 15 (11.7%), p = 0.004) were related to hyponatremia compared with normonatremia (9 (7.0%), p = 0.004). The level of mortality increased as sodium levels worsened. An adjusted Cox analysis showed that there was a relationship between hyponatremia and mortality (hazard ratio = 2.1; 95% confidence interval = 1.2-3.7; p = 0.008). Conclusions Admission hyponatremia is associated with higher in-hospital and 30-day mortality in HF patients, particularly those with low ejection fraction. Regular sodium monitoring and prompt correction can enhance early risk stratification and short-term outcomes.