Pass the Salt? Lack of Evidence for Low Salt in CHF

December 14, 2018

Written by Clay Smith

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Evidence for a low salt diet in patients with congestive heart failure (CHF) isn’t strong or conclusive. Advising a strict, low-salt diet may still be the right advice, but we just don’t have much evidence to guide us.

Why does this matter?
Eating a low salt diet is almost axiomatic for patients with CHF. Salt intake leads to fluid intake, which leads to volume overload, elevated BP, and all manner of bad things, right? The problem is, the evidence base for a low-salt diet just isn’t great. CHF is a core disease we regularly treat, and we need to be aware of major developments like this.

Would you like soy sauce with that?
This was a systematic review of 9 RCTs, 479 patients, to assess whether a low salt diet in patients with CHF reduces mortality or other cardiovascular outcomes and, secondarily, rate of hospitalization, length of stay, change in New York Heart Association (NYHA) functional status (i.e. dyspnea), adherence to the low-salt diet, and change in blood pressure. No studies addressed the primary outcomes. Just 2 outpatient studies addressed the secondary outcomes. These had conflicting results: 2 said a low salt diet did not lead to improvement and 2 said it did. And that is all we can glean from this review. The evidence for outcomes that matter in CHF is simply not available. So, should we advise CHF patients to drench food in soy sauce and get an order of fried pickles? Maybe not yet. But are we on solid ground to recommend a strict, low-salt diet? No, we are not. Several upcoming studies should help address this question.

Source
Reduced Salt Intake for Heart Failure: A Systematic Review. JAMA Intern Med. 2018 Nov 5. doi: 10.1001/jamainternmed.2018.4673. [Epub ahead of print]

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