Article posted by MedPage Today on patients receiving dietary counseling rather than pre-prepared meals.
Patients with chronic kidney disease (CKD) showed significantly improved blood pressure and hydration status when put on a sodium-restricted diet in a brief cross-over trial.
Importantly, the diet was not composed of pre-prepared low sodium meals. Instead, participants devised their own meals based on counseling they received from dietitians using motivational interview techniques, reported Rajiv Saran, MD, of the University of Michigan in Ann Arbor, and colleagues.
Compared with that of control group patients on their usual diet, the systolic blood pressure of patients on a low-sodium diet was an average of 10.8 mm Hg lower (95% CI -17.0 to -4.6; P<0.005) after four weeks, Saran and colleagues said in the Clinical Journal of the American Society of Nephrology.
Whole-body extracellular volume decreased by 1.02 L (95% CI -1.48 to -0.56; P<0.001) in the treatment group compared with the control group. Urinary sodium decreased by 57.3 mEg/hr (95% CI -81.8 to -32.9; P<0.005) and body weight decreased by 2.3kg (95% CI -3.2 to -1.5; P<0.005), the researchers reported.
The albumin:creatinine ratio did not change significantly, and mean serum creatinine increased slightly in the treatment group (0.1 mg/dL (95% CI -0.01 to 0.2; P=0.06), the study found.
“While prior studies have documented the efficacy of dietary sodium restriction in reducing blood pressure in the general hypertensive population, few have explored this in the CKD population,” Saran and colleagues wrote.
“We found that reducing sodium in the diet helps to significantly reduce blood pressure and reduce the excess fluid retention that is common among patients with kidney disease,” Saran said in a statement.
“This did not require complicated pre-cooked meals and was simply based on common sense advice given by trained dietitians that helps patients understand what it takes to reduce salt in their diets and what the potential benefits are likely to be,” he said.
The randomized, crossover trial included 58 adult patients with stage 3-4 CKD. They were 60% male, 43% diabetic, and 93% hypertensive, with a mean age of 61 years. Participants followed a sodium restricted diet (less than 2 g/day) or their usual diet for 4 weeks, followed by a 2-week washout period and a 4-week crossover phase.
During the sodium restricted diet phase of the study, dietitians provided in-person counseling at baseline, week two, and week four using motivational interviewing techniques. Dietitians also called patients at weeks one and three to maintain motivation, assess compliance, and offer advice. Adherence to the low-sodium diet was also assessed by 24-hour urinary sodium excretion.
The primary outcome was change in hydration status from baseline to 4 weeks. Secondary outcomes included 4-week changes from baseline in ambulatory blood pressure, body weight, and albuminuria.
One limitation of the study was a violation in the randomization procedure at one of the two study sites, resulting in the overall results being driven predominantly by results at the other site. “In particular, the benefits … with respect to hydration status (1.48 L reduction in extracellular volume), weight (3.4 kg loss), and systolic ambulatory blood pressure reduction (17.9 mmHg) are more compelling when the randomized single-center results were examined (N=35),” Saran and colleagues wrote.
“The intervention proved safe, although a slight increase in serum creatinine was observed. This effect was more pronounced at the site where sodium-reduced diet adherence was greater. With decreases in extracellular volume and blood pressure, the slight rise in serum creatinine could relate to small reductions in intraglomerular pressure, analogous to the slight rise in serum creatinine following ACE inhibitor initiation,” the investigators said.
“Optimal blood pressure control remains a cornerstone of CKD management. In this randomized, crossover trial, we have demonstrated the feasibility and efficacy of dietary sodium restriction using motivational interviewing without invoking pre-prepared meals, in effecting meaningful improvements in both hydration status and blood pressure among patients with CKD. The intervention was well tolerated and no clinically significant adverse outcomes were observed,” the investigators concluded.
A larger, longer-term clinical trial is warranted to explore and confirm these results, they said.
Source: MedPage Today