The relationship between sodium dietary intake and fluid retention in inpatients with heart failure

Background: Heart failure is a syndrome with high mortality. Patients’ re-hospitalizations were often due to fluid overload symptoms. Although there were some research using dietary sodium as an intervention to export low dietary sodium effect on fluid overload in heart failure, few reports about amount of daily dietary sodium in patients with heart failure. In Taiwan, data of amount of daily dietary sodium in patients with heart failure were not yet collected. Aims: Inpatients with heart failure were invited to participate in this study. The purposes of this study were 1) to investigate dietary sodium intake and severity of fluid overload symptoms, 2) to explore the relationship between dietary sodium intake and severity of fluid overload symptoms, 3) to compare amount of dietary sodium intake and severity of fluid overload symptom under variance of dietary source and disease severity. Designs: This study design was a non-experimental research. Methods: Patients were recruited using convenience sampling from a medical center in northern Taiwan. The inclusion criteria were as follows: alert and had clear thinking, with ability to speak Chinese or Taiwanese, serum creatinine ≦ 2.54 mg/dL (male) or ≦2.06 mg/dL (female) in the latest week. The exclusion criteria were as follows: dementia, hepatic disease, renal disease, peripheral vascular disease, or respiratory disease, fever and diarrhea based on medical record; not available for urine collection, under ventilator, hemodialysis, blood transfusion, intravenous saline infusion and fasting treatment. A total of 116 patients were invited to join this study. Five out of 116 patients discharged during study. Eleven out of 116 rejected the study. Finally, a total of 100 patients entered the study. Fluid Overload Symptoms Scale and biochemical analyzes (Hitachi 7600 series automation system clinical analyzer) were major instruments for data collection. All analyses were conducted with SPSS version 17. The descriptive statistics used in the study includes range, mean ± standard deviation, frequency and percentage. The inferential statistics includes Pearson correlation, Spearman rho, t-test, and one-way ANOVA. Result: It was found that the patients had a mean age of 73 ± 14 years; 63% were males; 66% had an education level the equivalent of or less than junior high school; 86% were married; 36% were New York Heart Association functional classⅢ. This result showed that: 1) mean dietary sodium intakes was 2.97 ± .57 gm/day; 2) different disease severity was not significant in the amount of daily dietary sodium intake (p = .31); 3) mean fluid overload symptom score was 6.62 ± 4.97 points (range: 0~18 points); 4) levels of disease severity were significant in fluid overload symptom score (p = .00); 5) there was no significant correlation between the amount of daily dietary sodium intake and the severity level of fluid overload (p = .70); 6) different dietary source was not significant in the amount of daily dietary sodium intake (p = .54); 7) heart failure patients’ dietary sodium intake amount was more than what was recommended from nursing instructions. Conclusions and Suggestions: The result of the study shows that patients’ average dietary sodium intake was 2.97 gm/day, and that sodium intake and severity of fluid overload was not significantly correlated. In addition, the results of this study also show that average patients’ sodium intake is higher than that recommended in nursing instructions; hence, the amount of dietary sodium intake is still an important issue in heart failure care. In this study, a Fluid Overload Symptom Scale was developed and exhibited reliability with construct and criterion validity in the measurement of severity of fluid overload symptoms, exhibiting the validity of the scale. Being a specific measurement tool for fluid overload symptoms in heart failure, the scale is certainly convenient for patients to use in self-monitoring.