Clinical Investigation
Three Gram Sodium Intake is Associated With Longer Event-Free Survival Only in Patients With Advanced Heart Failure

https://doi.org/10.1016/j.cardfail.2010.11.008Get rights and content

Abstract

Background

There is limited evidence to support the recommendation that patients with heart failure (HF) restrict sodium intake. The purpose of this study was to compare differences in cardiac event-free survival between patients with sodium intake above and below 3 g.

Methods

A total of 302 patients with HF (67% male, 62 ± 12 years, 54% New York Heart Association [NYHA] Class III/IV, ejection fraction 34 ± 14%) collected a 24-hour urine sodium (UNa) to indicate sodium intake. Patients were divided into 2 groups using a 3-g UNa cutpoint and stratified by NYHA Class (I/II vs. III/IV). Event-free survival for 12 months was determined by patient or family interviews and medical record review. Differences in cardiac event-free survival were determined by Kaplan-Meier survival curve with log-rank test and Cox hazard regression.

Results

The Cox regression hazard ratio for 24-hour UNa ≥ 3 g in NYHA Class I/II was 0.44 (95% confidence interval [CI] = 0.20-0.97) and 2.54 (95% CI = 1.10-5.84) for NYHA III/IV after controlling for age, gender, HF etiology, body mass index, ejection fraction, and total comorbidity score.

Conclusions

These data suggest that 3 g dietary sodium restriction may be most appropriate for patients in NYHA functional Classes III and IV.

Section snippets

Design, Setting and Participants

This was a prospective observational study of patients with HF recruited from outpatient clinics associated with 6 large community hospitals or academic medical centers in Kentucky, Georgia, Indiana, and Ohio.

A total of 349 patients were eligible for this study. One patient declined to participate, 7 patients withdrew, 3 patients were lost to follow-up, and 36 were determine to have incomplete 24-hour urines based on urine collection logs or 24-hour urinary sodium excretion (UNa) values below

Sample Characteristics

Sample characteristics are shown in Table 1. The majority of patients were older than age 65 years (23-97 years). More than a half of the patients were obese. As a group, patients were primarily in NYHA functional Class II and III. There were no differences in frequency of prescribed medications or in diuretic doses between the stratified groups. Other patient characteristics were similar except those in NYHA Class I/II had a slightly higher mean LVEF and a lower total comorbidity score than

Discussion

To the best of our knowledge, this was the first prospective study to demonstrate that a specific level of sodium intake was associated with event-free survival of patients with HF. The most surprising finding was the differences in event-free survival between NYHA functional classes using the 3 g UNa cut point. Unexpectedly, patients at NYHA Class I/II with UNa less than 3 g had shorter event-free survival than NYHA Class I/II patients with higher UNa. More consistent with the current

Conclusion

Prior researchers demonstrating worse event-free survival in patients on low-sodium diets included fluid restrictions and diuretic doses that are not reflective of the typical patient with HF.11, 19 The study in which patients with medically compensated HF showed no evidence of sodium retention and better hemodynamic responses while consuming a high sodium diet was short term with no event-free survival data.20 None of these studies included comparisons of patients with different levels of HF

Acknowledgments

The authors would like to acknowledge the following for their contribution to the conduct of this study. JinShil Kim, PhD, RN, Ajou University, South Korea; Heather Jaynes, RN, MSN, Rebecca Sloan, PhD, RN, and Ms. Laura Parker, Indiana University School of Nursing; Armina Gradus-Pizlo, MD, Director, Advanced Heart Care Program, Clarian Health Partners, Indianapolis, IN; Joan Barr, RN, MSN, Advanced Heart Care Program, Clarian Health Partners; and Heather Payne Emerson, PhD, RD, Murray State

Disclosures

Supported in part by a grant from NIH NINR R01 NR 009280, General Clinical Research Centers at University of Kentucky: M01RR02602, Emory University: M01RR0039, and Indiana University: MO1 RR000750 and by NIH, NINR Center grant 1P20NR010679 to the University of Kentucky College of Nursing.

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