Moderate dietary sodium restriction is better than medication increase for chronic kidney disease

When chronic kidney patients use salt more moderately, RAAS medication has a much greater effect on blood pressure and protein loss. Cutting salt intake to the level of 6 grams per day, as suggested in general dietary guidelines, will already have the desired effect. This is a much more effective solution for chronic kidney patients than increasing their medication, a study conducted by nephrologists from the University Medical Center Groningen and the ZGT Almelo hospital concludes, and which has just been published in the British Medical Journal, a leading publication.

For chronic kidney patients the most important treatment to counter further kidney function impairment consists of lowering blood pressure and decreasing urinary protein loss, using drugs called ACE inhibitors that influence the renin-angiotensin-aldosterone system (RAAS). However, not all patients respond to the treatment adequately.

Research results

This study, conducted by the ‘Holland Nephrology Study Group’ (HONEST) and coordinated by the UMCG and ZGT Almelo hospital, shows that moderating salt intake greatly improves the effect of ACE inhibitors on blood pressure and urinary protein loss. Cutting salt intake to about 6 grams per day, the level suggested in general dietary guidelines, will already have the desired effect. The study also investigated the effect of adding an extra drug to inhibit the RAAS, an angiotensin receptor blocker. This type of dual RAAS blockade is often used in practice, but the study proved that this is much less effective than decreasing salt intake. If the dual RAAS blockade is combined with decreased salt intake it does have a slight positive effect on urinary protein loss.

Good news for chronic kidney patients

The results are good news for chronic kidney patients as they show that they can improve their condition by adopting a healthier lifestyle. The fact that salt intake need only be brought back to the general dietary guideline is encouraging as well. A healthy salt intake is required, not a drastic cutback in salt use. The reviewers for the British Medical Journal were extremely positive about the study, as its design comparing extra medication to a combination of medication and a change in lifestyle entailed a unique approach.

HONEST study

The study was conducted by a group of nephrologists in the north-eastern Netherlands, collaborating in the ‘Holland Nephrology Study Group’ (HONEST). In addition to the UMCG and ZGT Almelo hospital, participants include MCL Leeuwarden and the Martini Hospital Groningen. The HONEST group conducts multicentre clinical studies that aim to improve the outcome of kidney disease, with a focus on the optimum combination of medication and lifestyle intervention. The results of a further four studies on optimizing kidney disease treatment are expected in the coming year.