Fractional Excretion of Sodium and Its Association with Prognosis of Decompensated Heart Failure Patients

Introduction: Diuretic resistance is a common problem in congestive heart failure patients. It has been defined clinically but can be defined objectively in terms of fractional excretion of sodium (FENa). Aim: Aim of the study was to find out the association of FENa with prognosis of decompensated heart failure patients. Materials and Methods: One hundred and seventy eligible patients with a primary diagnosis of decompensated heart failure were enrolled and patients were categorized into two groups on the basis of baseline FENa-Group A (65 patients) with diuretic resistance with FENa <0.2% and Group B (105 patients) sensitive to diuretics with FENa >= 0.2%. The patients were followed-up during the hospital stay for the time taken for improvement from NYHA functional class IV to class II. They were followed telephonically at 30 days post admission for all cause mortality. Result: The mean time taken to improve from NYHA functional class IV to class II were 146 hours for FENa<0.2% and 60 h for FENa >= 0.2% (p<0.0001). There was a fair negative correlation between FENa and time taken for improvement from NYHA functional class IV to class II with correlation coefficient being -0.4842. Multiple linear regression analysis showed FENa (standardized "B" is -0.480, p<0.001) and LVEF (standardized "B" is -0.182, p=0.007) as significant predictors of time taken for improvement from NYHA functional class IV to class II. The 30 days all cause mortality was significantly associated with level of Fena (p < 0.001) and was inversely proportional. Conclusion: CHF patients with FENa <0.2% takes longer time to recover from NYHA functional class IV to class II. 30 days all cause mortality was also significantly higher among CHF patients with FENa <0.2%. Measuring baseline FENa and regulating diuretic dose accordingly at admission to hospital may probably improve the prognosis of CHF patients.