Hyponatremia in patients hospitalized with heart failure: a condition often overlooked in low-income settings

BACKGROUND Hyponatremia is a common electrolyte abnormality in patients with heart failure (HF). It is independently associated with increased short-term and long-term morbidity and mortality. The main objective of this study was to assess patterns of hyponatremia and its association with discharge outcomes in patients with HF admitted to a teaching hospital in Ethiopia. PATIENTS AND METHODS This is a descriptive, prospective, hospital-based cohort study of patients with HF admitted to Jimma University Hospital, Ethiopia, between November 1, 2013 and July 31, 2014. A structured questionnaire was used to collect information on sociodemographic characteristics, clinical profile at admission, and outcomes at discharge. Plasma sodium concentration was analyzed at admission for all patients. The relationship between hyponatremia at admission and in-hospital mortality, as well as length of hospital stay, was assessed using both bivariate analysis and multivariable logistic regressions. The level of statistical significance was set at P<0.05. RESULTS Of 152 participants admitted with HF, 44 (28.9%) had hyponatremia, which is defined as serum sodium level <135 mmol/L. Patients on salt restriction, on chronic diuretic treatment (furosemide and spironolactone), and with impaired renal function at admission were found to be highly affected. Hyponatremia was found to be associated with increased in-hospital mortality (P=0.008) and longer hospital stay (16.6 vs 12 days, P<0.001). Patients with hyponatremia also had lower blood pressure and poor functional status at discharge. CONCLUSION This study demonstrates that hyponatremia is highly prevalent in patients hospitalized with HF and is associated with increased in-hospital mortality and longer hospital stay. Thus, great emphasis should be given to identify high-risk patients, and prevention and early detection of hyponatremia to prevent its deleterious effects. Large-scale national studies are also needed to complement our findings.