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Rapid response to:

Practice Guidelines

Management of hypertension: summary of NICE guidance

BMJ 2011; 343 doi: (Published 25 August 2011) Cite this as: BMJ 2011;343:d4891

Rapid Response:

Salt restriction versus a fourth add-on drug for treatment of resistant hypertension at step 4. NICE Guidance

Dear Editor,

The new edition of the NICE guidelines of Hypertension[1, 2]
recommends for treatment of resistant hypertension at step 4, either the
use of a higher dose of thiazide-like diuretic, or the addition of the
aldosterone antagonist spironolactone. Both strategies work reducing the
intravascular volume expansion that is almost always present in resistant
hypertension[3], by forcing sodium and water renal excretion.

We miss in this guide and others, more concern for the other
mechanism that prevents volume overload in resistant hypertension which is
the reduction of salt ingestion and consequently water retention.

Unfortunately, the clinical effect on blood pressure of sodium
restriction in patients with resistant hypertension has insufficiently
been studied. Only a recent 4-week randomized cross-over study which
included 12 patients[4] suggests, that patients with resistant
hypertension are exquisitely salt sensitive. The blood pressure reduction
achieved during the low-salt ingestion period, as high as 22.7/9.1 mm Hg,
was estimated as being equivalent to adding 2 antihypertensive

Many hypertension clinics and primary-care physicians use 24-hours
urinary sodium measurements as a method to detect a poor adherence with
salt dietary restriction. Our experience is that a value of sodium
excretion >120 mmol/24-hour allow clinicians to convince patients that
they are not doing sufficient efforts with sodium intake restriction. Many
patients change their attitude, improve their accomplishment with our
advice and finally reach the blood pressure objectives

While more evidence be available, we believe that to control
resistant hypertension and to diminish iatrogenic risk, it is appropriate,
before or during pharmacologic modifications at step 4, not only to
attempt dietary modification again, but also to provide assurance that
salt restriction is effective by performing 24-hour urinary sodium

[1] National Institute for Health and Clinical Excellence.
Hypertension: clinical management of primary hypertension in adults.
CG127. 2011.

[2] Guidelines: Management of hypertension: summary of NICE guidance.
Taryn Krause,
Kate Lovibond, Mark Caulfield, Terry McCormack, Bryan Williams, on behalf
of the Guideline Development Group. BMJ 2011;343:doi:10.1136/bmj.d4891
(Published 25 August 2011)

[3] Gaddam KK, Nishizaka MK, Pratt-Ubunama MN, Pimenta E, Aban I,
Oparil S, et al. Characterization of resistant hypertension: association
resistant hypertension, aldosterone, and persistent intravascular volume
Arch Intern Med. 2008;168:1159-64. [PMID: 18541823]

[4] Pimenta E, Gaddam KK, Oparil S, et al. Effects of dietary sodium
reduction on blood pressure in subjects with resistant hypertension:
results from a randomized trial. Hypertension. 2009;54:475-81

Competing interests: No competing interests

16 September 2011
F. Javier Sierra Alonso
Family Physician
M. E. Santiago Paz*, M. Sanz Sanz and J. Rosado Martin. * Nurse
Las Aguilas Primary Care Unit, Consejeria de Sanidad. Madrid. Spain