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Contrary to conventional wisdom, aggressively restricting fluids and sodium intake in acute decompensated heart failure patients did not improve outcomes, a small randomized trial found.

At 3 days, there was no significant difference between those randomized to aggressive treatment and those designated as controls in weight loss, urine output, clinical improvement, amount of IV diuretics, and time to discharge, according to Luis Beck-da-Silva, MD, ScD, Hospital de Clinicas de Porto Alegre in Brazil, and colleagues.

Similarly, at 30 days post-discharge, there was no significant difference between the groups in hospital readmission rates, researchers reported online in JAMA Internal Medicine.

The intervention group, however, did have more readmissions at 30 days, when compared to the control group (11 versus 7), "suggesting a trend in favor of the regular diet," commented Melvin D. Cheitlin, MD, of the University of California San Francisco, in an accompanying editorial.

He also noted that those whose fluid and sodium intake was aggressively restricted had significantly worse congestion at 30 days compared with standard of care (clinical congestion score 7.9 versus 6.0, P=0.01). Interestingly, at 3 days, the control group had a higher clinical congestion score (7.1 versus 6.4).

"Understanding the mechanism involved in acute decompensated heart failure is as important as understanding the congestion," Valentin Fuster, MD, of the Mount Sinai Medical Center in New York City, told 乌鸦传媒.

He said the complexity of acute heart failure involves more than just restricting sodium and fluids, that there is a cascade of processes that lead to hemodynamic failure.

One of the main differences between both groups was the perceived thirst, which was significantly higher in the intervention group (visual analog scale 5.1 versus 3.4, P=0.01).

"This finding adds a negative component to an intervention that, thus far, had appeared neutral in terms of weight loss and relief of clinical congestion," Beck-da-Silva and colleagues said.

Cheitlin opined that the hunger and thirst of those in the intervention group after discharge may have "led to greater salt and water intake."

Researchers noted that two previous randomized trials evaluating fluid and sodium intake in those with acute decompensated heart failure have produced different results. They suggested the studies may have been underpowered.

In addition, non-randomized studies looking at salt reduction in heart failure had a wide range of sodium intake, adding more uncertainty to arriving at an evidence-based recommendation.

At the onset of their investigation, Beck-da-Silva and colleagues proposed that aggressive fluid restriction and a low-sodium diet would have a positive impact on weight loss and clinical stability.

To be eligible for enrollment, patients had to have a left ventricular ejection fraction of 45% or less, and a hospital stay of no more than 36 hours after admission.

The maximum fluid intake was 800 mL/d, while the maximum sodium intake was 800 mg/d.

Only 9% of the 813 patients screened between 2009 and 2012 were eligible for the study.

Baseline characteristics were similar between the 38 patients randomized to the intervention and the 37 controls. The mean age was 61 and most were men and white.

From the evidence of their study and those of others, the investigators concluded fluid restriction has a neutral effect in these patients. There is a suggestion that the modern management of heart failure patients, with a wide range of effective drugs, dilutes any effect that fluid restriction might provide.

Regarding sodium intake, researchers concluded that there is evidence "drawn from a combination of multiple interventions" that increased sodium intake provides some benefits.

From the American Heart Association:

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