Effects of Dietary Sodium Restriction on Outcomes in HF
Effects of Dietary Sodium Restriction on Outcomes in HF
A total of 451 patients underwent screening between May and December 2012, of which 38 patients were enrolled. Most (63%) of patients screened did not meet the inclusion criteria. Being in NYHA class I or IV was the main reason why patients did not qualify for this study. During follow-up, 2 patients dropped out (one in each group) and 1 died (in the moderate-sodium diet group) (Figure 1). Of the overall study population, 95% (n = 37) was white, 3% (n = 1) was Afro-American, and 3% (n = 1) was South Asian. Baseline characteristics are shown in Table I. Patients in both groups did not differ significantly, and most of the patients were NYHA class II. There were no differences between groups in the baseline use of cardiac medications.
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Figure 1.
Study cohort.
At the end of the 6 months of follow-up, median of sodium intake dropped significantly in both groups, from 2137 to 1398 mg/d (median change, 931 [251, 1903], P =.001) in the low-sodium diet group and from 2678 to 1461 mg/d (median change, 898 [173, 1337], P = .002) in the moderate-sodium diet group (Table II). There was no difference between the 2 groups for the change of sodium intake over the 6 months (931 vs 898, P = .50). No significant changes in energy intake or total fluid intake were seen in either group (Table II).
Median BNP levels decreased for 6 months in the low-sodium diet group (216–71 pg/mL, with a median change of 51 pg/mL [−2, 331]; P = .006), whereas no significant changes were found in the moderate-sodium diet group (171–188 pg/mL, with median change of 36 pg/mL [−51, 62]; P = .67) (Table II). No significant difference was found for comparison of changes between groups (P = .18).
For 6 months, median KCCQ clinical score increased in the low-sodium diet group (63–75 points, with median change of 9 [2, 15]; P = .006) and trended to increase in the moderate-sodium group (66–73 points, with median change of 6 [−1, 15], P = .07; P = .41 between groups) (Table II). KCCQ overall scores followed a similar pattern to the clinical score (60–65 points, with a median change of 6 [0.5, 22], P = .04, for low-sodium group; 66–72 points, with median change of 5 [−3, 15], P = .07, for moderate group; P = .44 between groups).
At the end of follow-up, there was no significant difference in NYHA class between moderate- and low-sodium groups (P = .87). Creatinine levels increased at 6 months in the moderate-sodium diet group but not in the low-sodium group (Table II). No significant changes were found for body mass index, systolic blood pressure, heart rate, the use and dose of loop diuretics and frequency of dyspnea, peripheral edema, and fatigue from baseline to 6 months in either group (data not shown).
When patients were reclassified according to the sodium intake achieved at the end of follow-up, there were no differences in distribution by sex and baseline age and ejection fraction between groups (data not shown). Patients with an average daily sodium intake ≤1500 mg/d at 6 months showed a significant reduction in BNP and improvement in the KCCQ clinical and overall scores. Conversely, the group of patients with a sodium intake >1500 mg/d at 6 months did not show significant changes from baseline to 6 months in BNP levels or KCCQ overall and clinical scores (Table III and Figure 2, Figure 3, Figure 4). Also, the proportion of patients that showed an improvement in NYHA class tended to be greater in the low-sodium than the moderate-sodium group (P = .08). Other results, including fluid intake and loop diuretic dose, did not differ significantly at follow-up between and within groups (data not shown).
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Figure 2.
Change in BNP over time by achieved dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change −50 (−272, −10), P = .01; within >1500 mg/d group: median change −1 (−51, 14), P = .72. Between groups, P = .08.
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Figure 3.
Change in KCCQ clinical score by achieved dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change 13.02 (2.09, 18.44), P = .003; within >1500 mg/d group: median change 1.36 (−1.04, 8.33), P = .18. Between groups, P = .08.
(Enlarge Image)
Figure 4.
Change in KCCQ overall score over time with dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change 9.37 (3.12, 20.06), P = .007; within >1500 mg/d group: median change 2.48 (−2.61, 7.46), P = .34. Between groups, P = .16.
Results
A total of 451 patients underwent screening between May and December 2012, of which 38 patients were enrolled. Most (63%) of patients screened did not meet the inclusion criteria. Being in NYHA class I or IV was the main reason why patients did not qualify for this study. During follow-up, 2 patients dropped out (one in each group) and 1 died (in the moderate-sodium diet group) (Figure 1). Of the overall study population, 95% (n = 37) was white, 3% (n = 1) was Afro-American, and 3% (n = 1) was South Asian. Baseline characteristics are shown in Table I. Patients in both groups did not differ significantly, and most of the patients were NYHA class II. There were no differences between groups in the baseline use of cardiac medications.
(Enlarge Image)
Figure 1.
Study cohort.
Dietary Intake
At the end of the 6 months of follow-up, median of sodium intake dropped significantly in both groups, from 2137 to 1398 mg/d (median change, 931 [251, 1903], P =.001) in the low-sodium diet group and from 2678 to 1461 mg/d (median change, 898 [173, 1337], P = .002) in the moderate-sodium diet group (Table II). There was no difference between the 2 groups for the change of sodium intake over the 6 months (931 vs 898, P = .50). No significant changes in energy intake or total fluid intake were seen in either group (Table II).
B-type Natriuretic Peptide Levels
Median BNP levels decreased for 6 months in the low-sodium diet group (216–71 pg/mL, with a median change of 51 pg/mL [−2, 331]; P = .006), whereas no significant changes were found in the moderate-sodium diet group (171–188 pg/mL, with median change of 36 pg/mL [−51, 62]; P = .67) (Table II). No significant difference was found for comparison of changes between groups (P = .18).
Quality of Life
For 6 months, median KCCQ clinical score increased in the low-sodium diet group (63–75 points, with median change of 9 [2, 15]; P = .006) and trended to increase in the moderate-sodium group (66–73 points, with median change of 6 [−1, 15], P = .07; P = .41 between groups) (Table II). KCCQ overall scores followed a similar pattern to the clinical score (60–65 points, with a median change of 6 [0.5, 22], P = .04, for low-sodium group; 66–72 points, with median change of 5 [−3, 15], P = .07, for moderate group; P = .44 between groups).
Other Clinical Measures
At the end of follow-up, there was no significant difference in NYHA class between moderate- and low-sodium groups (P = .87). Creatinine levels increased at 6 months in the moderate-sodium diet group but not in the low-sodium group (Table II). No significant changes were found for body mass index, systolic blood pressure, heart rate, the use and dose of loop diuretics and frequency of dyspnea, peripheral edema, and fatigue from baseline to 6 months in either group (data not shown).
Post Hoc Analysis
When patients were reclassified according to the sodium intake achieved at the end of follow-up, there were no differences in distribution by sex and baseline age and ejection fraction between groups (data not shown). Patients with an average daily sodium intake ≤1500 mg/d at 6 months showed a significant reduction in BNP and improvement in the KCCQ clinical and overall scores. Conversely, the group of patients with a sodium intake >1500 mg/d at 6 months did not show significant changes from baseline to 6 months in BNP levels or KCCQ overall and clinical scores (Table III and Figure 2, Figure 3, Figure 4). Also, the proportion of patients that showed an improvement in NYHA class tended to be greater in the low-sodium than the moderate-sodium group (P = .08). Other results, including fluid intake and loop diuretic dose, did not differ significantly at follow-up between and within groups (data not shown).
(Enlarge Image)
Figure 2.
Change in BNP over time by achieved dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change −50 (−272, −10), P = .01; within >1500 mg/d group: median change −1 (−51, 14), P = .72. Between groups, P = .08.
(Enlarge Image)
Figure 3.
Change in KCCQ clinical score by achieved dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change 13.02 (2.09, 18.44), P = .003; within >1500 mg/d group: median change 1.36 (−1.04, 8.33), P = .18. Between groups, P = .08.
(Enlarge Image)
Figure 4.
Change in KCCQ overall score over time with dietary sodium intake (> or ≤1500 mg/d). Within ≤1500 mg/d group: median change 9.37 (3.12, 20.06), P = .007; within >1500 mg/d group: median change 2.48 (−2.61, 7.46), P = .34. Between groups, P = .16.
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