Abstract 295: Serum Sodium-Potassium ratio as a predictor of long-term Heart Failure morbidity.

Abstract

Background: Electrolyte abnormalities particularly hyponatremia and hypokalemia are known to be associated with poorer outcomes in heart failure (HF). Some other studies have also suggested that the Sodium-Potassium ratio (Na/K) could serve as a prognostic marker of cardiovascular disease (CVD). However, most of these studies relate mainly to the intake of the electrolytes as opposed to the serum concentrations, suggesting that decreasing sodium intake and increasing potassium intake could reduce CVD risk. Less is known about the relationship between the serum Na/K ratio and outcomes in HF. Given that serum electrolytes are routinely monitored during HF management in the hospital, we sought to retrospectively examine any prognostic impact of the admission and discharge Sodium-Potassium ratios on outcomes. Methods: Outcomes (HF admissions, Length of stay & cardiac admissions, non-cardiac admissions, and emergency room visits) were assessed for 331 HF patients from the Meharry Heart Failure Registry- a comprehensive retrospective HF database comprised of patient care data from January 2006 to December 2008. The database population consists of 72% African-American (AA), 19% Caucasian, and 9% other. The mean age of the cohort is 61 years (age range of 25-98) 37% of whom are females. Normal serum sodium and potassium levels were defined per the laboratory standards (i.e. normal serum Sodium range of 135mmol/L-145mmol/L and Potassium 3.5mmol/L-4.5mmol/L respectively). The individual admission and discharge serum Sodium-Potassium ratios were calculated and the relationship with heart failure outcomes determined using the Spearman correlation and Wilcoxon-Mann-Whitney test. Results: Our study showed no significant correlation between admission and or discharge serum Na/K ratio and HF outcomes (P value 0.339 - 0.987 with admission ratios and 0.101 - 0.699 with discharge ratios). These findings were consistent even in subgroup analysis (gender, Preserved versus reduced EF and Age > versus < 60). Conclusions: Our study suggests that there is no relationship between either the admission and or discharge Sodium-Potassium ratio and heart failure morbidity. These findings may be because most of the subjects had normal serum Sodium and Potassium levels therefore minimizing any differences. There is also the inherent biases associated with retrospective studies making it difficult to control for various contributing factors. A larger prospective study might be helpful in elucidating this further.