Cochrane Salt/Blood-Pressure Message Blasted in the Lancet

[Guest guest]

Two preventive-medicine experts in the UK are crying foul over a recent and

controversial meta-analysis that concluded cutting salt consumption would

have no clear health benefits [1]. In a Comment published in the July 30,

2011 issue of the *Lancet*, *Dr Feng J He *(Queen University, London,

UK) and* Dr Graham A MacGregor *(Wolfson Institute of Preventive Medicine,

Barts, London, UK) say that the meta-analysis published simultaneously by

and colleagues in the *Cochrane Review* [2] and the *American Journal

of* *Hypertension* [3] and press release that accompanied it " reflect poorly

on the reputation of the Cochrane Library and the authors. "

As previously reported by *heartwire *, et al's meta-analysis

included seven randomized controlled trials of dietary salt reduction in

normotensives (three studies), hypertensives (two studies), a mixed

population (one study), and one trial of patients with heart failure.

At follow-up, relative risks for all-cause mortality and cardiovascular

mortality for both normotensives and hypertensives were only mildly to

moderately reduced, and not to a statistically significant degree. In

congestive heart failure patients, salt restriction actually significantly

increased all-cause death.

He and MacGregor, in their Comment, reanalyze the same data but combined the

normotensives and hypertensives. They also omitted the heart-failure

trial--a group of " very ill " patients taking large doses of diuretics in

whom salt restrictions would seldom be recommended, MacGregor observed. In

the combined patient analysis, they find a now statistically significant 20%

reduction in cardiovascular events and a nonsignificant reduction in

all-cause mortality.

" The results of our reanalysis, contrary to the claims by and

colleagues, support current public-health recommendations to reduce salt

intake in the whole population, " He and MacGregor conclude.

*Misleading Public Messages?*

In an interview with *heartwire *, MacGregor, who is also chair of both the

*Consensus Action on Salt and Health *and the *World Action on Salt and

Health*, said he and his coauthor felt et al's conclusions in the

paper itself were measured. But they take issue with both the " Plain

Language Summary " printed within the main article and with a press release

sent out by the publisher.

" The press release and the paper have seriously misled the press and thereby

the public, " they write. " For example, in the UK the *Daily

Express*front-page headline read, 'Now salt is safe to eat--Health

fascists proved

wrong after lecturing us all for years,' and there were similar headlines

throughout the world. "

" In actual fact, the findings we have when we reanalyze the data are the

exact opposite of what the others conclude in their attention-grabbing

headlines, " MacGregor told *heartwire *.

*An Urgent Retort*

Asked why their comment was sent to the *Lancet* rather than one of the two

publications in which the et al paper was published, MacGregor cited

the need for a swift, high-profile response.

" Obviously this is somewhat urgent--this caused headline news around the

world, and the [salt-industry trade association] *SALT Institute* has a huge

amount on its website about this, " he said. " We wanted to get this

correction in [print] very quickly and get it some publicity, because it's

obviously totally wrong to claim salt reduction is not beneficial. " In fact,

he points out, et al's review " doesn't say that; it says we need more

evidence. We say it is [beneficial]; we've done this reanalysis, and we've

got the evidence. In fact, all the evidence about salt is

overwhelming. . . . It all shows that salt is a major factor bringing up our

blood pressure. "

Asked to respond to He and MacGregor's Comment, *Dr Rod * (University

of Exeter, UK) told *heartwire * that he and his coauthors are preparing a

" formal letter in response " that they plan to submit to the *Lancet*, and

" We'd rather make use of our letter as our communication vehicle in this

case. "

*He and MacGregor declare they have no conflicts of interest.*

www.medscape.com

--

Ortiz, MS, RD

*The FRUGAL Dietitian* <http://www.thefrugaldietitian.com>

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