Serum Sodium Profile of Congestive Heart Failure Patients and its Impact on Their Outcome at Discharge

Introduction Patients with congestive heart failure (CHF) readily present with electrolyte imbalance which commonly includes deficiencies of sodium, potassium, and magnesium. Hyponatremia occurs in advanced stages of CHF and is associated with adverse disease outcome-longer hospital stay, severity of CHF, and increased risk of mortality. Methods In this observational, single-center, prospective, case-control study adult patients admitted with clinical diagnosis of CHF were included after informed consent. Their demographic, clinical, and biochemical profile was attained. Patients with low serum sodium (hyponatremia) were grouped as "cases" and patients with normal serum sodium profile (normonatremia) were grouped as "controls". Factors associated with both groups and their hospital outcome were compared. SPSS for Windows version 16 (SPSS Inc., Chicago, IL, USA) was utilized. Results Hyponatremia (serum sodium <135 mmol/L) was present in 58/189 (30.7%) patients admitted with CHF. Younger patients with non-ischemic CHF, and history of previous diagnosis, treatment, and hospitalization due to CHF were more likely to be affected. Diabetic nephropathy, chronic kidney disease, salt-restricted diet, drugs including furosemide, spironolactone, and angiotensin-converting enzyme inhibitors, low serum potassium, and reduced GFR were also related to hyponatremia. Hyponatremic CHF patients showed adverse hospital outcome on all parameters including higher death rate (12% vs. 0.8%), longer duration of hospital day, and deranged blood pressures and severe CHF at the time of discharge. Conclusion Hyponatremic CHF patients are associated with prolonged hospital stay, more severe form of CHF, and deranged blood pressures. Overall, hyponatremia is an indirect clinical indicator of circulatory dysfunction and should guide a clinician for closer observation as outcomes could be poor. These patients also have higher in-hospital mortality risk.