OLA Tweet: Salt Restriction in CKD

Written by Meguid El Nahas on Sunday, 19 February 2017. Posted in OLA Blog

OLA Tweet: Salt Restriction in CKD
Prof Pierre Delanaye TWEETED: 
 
A cheap and (relatively) simple intervention to improve HTA in CKD! Don't forget it! This is a RCT!
 
 
Clin J Am Soc Nephrol. 2017 Feb 16. pii: CJN.01120216. doi: 10.2215/CJN.01120216. [Epub ahead of print]

A Randomized Crossover Trial of Dietary Sodium Restriction in Stage 3-4 CKD.

BACKGROUND AND OBJECTIVES:

Patients with chronic kidney disease (CKD) are often volume expanded and hypertensive. Few controlled studies have assessed the effects of a sodium-restricted diet (SRD) in CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS:

We conducted a randomized crossover trial to evaluate the effect of SRD (target <2 g sodium per day) versus usual diet on hydration status (by bioelectrical impedance spectroscopy) and blood pressure (BP) between May of 2009 and May of 2013. A total of 58 adults with stage 3-4 CKD were enrolled from two academic sites: University of Michigan (n=37) and University of North Carolina at Chapel Hill (n=21); 60% were men, 43% were diabetic, 93% were hypertensive, and mean age was 61 years. Participants followed SRD or usual diet for 4 weeks, followed by a 2-week washout period and a 4-week crossover phase. During the SRD, dieticians provided counseling every 2 weeks, using motivational interviewing techniques.

RESULTS:

Whole-body extracellular volume and calf intracellular volume decreased by 1.02 L (95% confidence interval [95% CI], -1.48 to -0.56; P<0.001) and -0.06 L (95% CI, -0.12 to -0.01; P=0.02), respectively, implying decreased fluid content on the SRD compared with usual diet. Significant reductions in urinary sodium (-57.3 mEq/24 h; 95% CI, -81.8 to -32.9), weight (-2.3 kg; 95% CI, -3.2 to -1.5), and 24-hour systolic BP (-10.8 mmHg; 95% CI, -17.0 to -4.6) were also observed (all P<0.01). Albumin-to-creatinine ratio did not change significantly and mean serum creatinine increased slightly (0.1 mg/dl; 95% CI, -0.01 to 0.2; P=0.06). No period or carryover effects were observed. Results were similar when analyzed from phase 1 only before crossover, although P values were modestly larger because of the loss of power.

CONCLUSIONS:

In this randomized crossover trial, implementation of SRD in patients with CKD stage 3-4 resulted in clinically and statistically significant improvement in BP and hydration status. This simple dietary intervention merits a larger trial in CKD to evaluate effects on major clinical outcomes.

Meguid El Nahas

Professor Meguid El Nahas PhD, FRCP

Chief Editor, OLA Director

Professor El Nahas was born in Cairo, Egypt and undertook his undergraduate medical education in...
Posted: 2 months 4 days ago by elnahas #21322
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How does this differ from adequate and optimal diuretic therapy; diuretics are also associated with lower BP and improved CVD outcomes; ALLHAT and other studies since some including CKD patients.
Posted: 2 months 4 days ago by arif.khwaja #21323
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Why take a pill when you can achieve the same through lifestyle.... surely we want to get away from the idea that the answer to everything is a pill... reserve diuretics for those who can't salt restrict
Posted: 2 months 4 days ago by elnahas #21324
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Try salt restriction in this day and age...and tell me if taking a pill is not easier...also in emerging countries, bread and processed food is salt..salt...salt...fancy dietary restrictions is not accessible to all and after all whats wrong with taking a diuretic if you have CKD3-5 and are hypertensive, as most are on diuretics anyway!?
Posted: 2 months 4 days ago by arif.khwaja #21325
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disagree.. diuretics have side effects - increased risk of gout and polyuria which is a curse for the elderly.
there is nothing fancy about making the food you eat... if you do that you can control the salt... lots of people do it successfully
Posted: 2 months 4 days ago by tukaram #21326
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"excess salt intake" is a learnt behaviour and there is evidence to suggest that it can be easily unlearned.
(Am J Clin Nutr August 1986 vol. 44 no. 2 232-243)
Agreed that current food environment is challenging to make such changes. There is clear vested interest of food industry to increase salt content of the food to make it more addictive.
Posted: 2 months 4 days ago by mecit #21327
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I agree with Dr.Arif
Salt restriction will help us to lower dosage of loop diüretics, Our struggle with hypokhelmia and üric acid will be less aggressive, another point is diüretics will not lessen amount of fluid we take by mouth but salt achieve
Posted: 2 months 3 days ago by elnahas #21328
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Here are some facts,

1. Salt restriction has been shown to lower BP for more than 40 years; since the DASH, and DASH-Salt studies.

2. In spite of the considerable interest fostered by Prof Graham McGregor worldwide about salt and health,
www.worldactiononsalt.com/

3. the world salt consumption is on the increase not decrease. I will not enter into the controversy surrounding his data and the level of salt restriction, etc...also note from the reference included that highest salt consumption is in emerging countries.
www.wcrf.org/int/cancer-facts-figures/li...isk/salt-consumption

4. also the relationship between salt restriction, BP and CVD outcomes is far from linear...(see attached paper and analysis)
www.ncbi.nlm.nih.gov/pubmed/28049345

[File Attachment: TheINTERSALTStudyandthecomplexrelationshipbetweensaltintakeandbloodpressure.pdf]


5. As to the loop diuretics scare mongering:
A. most patients in CKD4-5 are on loop diuretics anyway
B. In these patients they seldom cause hypokalemia
C. Hyperuricemia is prevalent in CKD3-5 and often asymptomatic

6. The data on diuretics and CVD protection is compelling since the ALLHAT data showing the Chlorthalidone was more cardioprotective than ACE inhibition with Lisinopril! Since data with other thiazides as well as indapamide confirmed cardioprotection. It is likely that the SPRINT study impact on Heart Failure/oedema was due to better use of diuretics.

7. Longterm compliance to dietary restrictions is always a challenge; in that respect short term studies are of little interest!
Posted: 2 months 2 days ago by delanaye #21335
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I agree with Arif...but basically I think that our role as a doctor is to recommend the best practice for the patient. Try to help him. I believe that every CKD patient stage 4 should benefit from of dietetician consultation. But then the patient do like he wants...

Very important from my point of view: maybe the question is not "Diet" OR ""thiazides" (loop diuretics are not natriuretic) but diet AND thiazides
Posted: 2 months 5 hours ago by elnahas #21340
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Whilst I do not totally write off the value of some salt restriction; i doubt its practicality and implementation on a large scale.

How many of those who are for salt restriction prescribe it....?!

What level of salt restriction to you instruct your patient to adhere to...?!

How do you monitor compliance...?!


PS: LOOP DIURETICS LIKE FUROSEMIDE ARE NATRIURETICS:

Loop diuretics are more diuretics (Water loss) than natriuretics (salt loss) ....but they have a natriuretic effect!

In fact, Frusemide is a potent natriuretic drug, which inhibits the Na(+)-K(+)-2Cl(-) cotransporter (NKCC)-2 in the ascending limb of the loop of Henle!

There is a useful and uptodate review on frusemide , a loop diuretic, published last year raising interesting points:
www.ncbi.nlm.nih.gov/pubmed/26911852
Posted: 2 months 4 hours ago by arif.khwaja #21341
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Adherence to medications or lifestyle is extememely poor in patients with chronic disease. Just because your prescribing diuretics doesn't mean patients are taking them. In fact adherence maybe as low as 30% for chronic disease patients taking multiple medications If you want to measure response to dietary intervention you can either do 24 hour urinary sodium or you can see if the patients BP improves with diet. If it doesn't improve with diet then it seems sensible to start diuretics... I just don't get why you would deny patients the opportunity to manage with diet if they want to.
Posted: 2 months 3 hours ago by elnahas #21342
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I have no problem with that....but, tell me when you last prescribed the low salt diet you are so keen upon;

how many grams did you recommend?

how often you measure 24h urine sodium output...?

all fine in theory, but do you practice what you preach?
Posted: 2 months 2 hours ago by tukaram #21345
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Dietary advice works best when provided by nephrologist (rather than nutritionist). I routinely counsel all my hypertensive CKD patients at their first visit about easy ways to curtail salt intake (and caloric intake if obese) in their diet, and its not uncommon to find a patient who will religiously adhere to it. In some of our nephrotic patients, I have seen urine sodium going undetectable.
Posted: 2 months 1 hour ago by elnahas #21346
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my advice was basic:

1. NO added salt to meals at the table (and this takes away at least 2g)

2. Minimise processed food; as these are more salt than food
Posted: 2 months 1 hour ago by arif.khwaja #21347
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I tell all hypertensive patients to reduce the salt in their diet....
I never prescribe a figure as for most of them salt counting in processed food is just too difficult. They key thing I tell them I s to call ok as much of their own for as possible so they can reduce salt and to minimise processed food - I never measure urinary sodium in patients on diuretic or low salt diets
- I am not sure how it changes management - however my friend Anderson does measure 24 hr urinart sodium and tells me it's very useful to give to patients as a way of guiding them through their diet and providing feedback on how they are doing - I have no problem with diuretics but in increasingly feel that the solution to hypertension in ckd isn't just thro drug therapy but a multifaceted approach
Posted: 2 months 1 hour ago by elnahas #21348
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NKF recommendations and tips....very middle class and not at all for low socio-economic classes struggling with food price and cost of living...same problem as obesity and its high prevalence in low socio-economic classes who rely on cheap processed and junk food for living...and have less time or income to afford all those "FRESH" meals!

www.kidney.org/news/ekidney/june10/Salt_june10
Posted: 2 months 54 minutes ago by arif.khwaja #21349
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I just dont see the harm in providing advice about a low salt diet- the idea that it's just for the middle classes in absurd.:. As Tukaram some people actually are desperate to do something - as it it gives them a sense of control... you can eat cheaply and healthy- but people need to be supported in how to do so
Posted: 2 months 45 minutes ago by elnahas #21350
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what I am referring to is the NKF advice, to buy all fresh...to avoid processed food...etc...thats NOT affordable by low socio-economic classes in many countries including the US, where junk food is the staple diet; so advice have to be real and address socio economic and market constraints to be effective.
Posted: 2 months 43 minutes ago by arif.khwaja #21351
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All Im saying is the advice you gave earlier - avoid adding salt at the table or when cooking and minimise processed food if possible- is important, and valid and can have a modest impact
Posted: 1 month 4 weeks ago by tukaram #21352
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At least in countries like India, its convinience more than cost that underlie the excess salt and calories cosumption. Healthy food isn't necessarily costly-although it may not be convinient. At least some may be able to choose health over convenience!

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