Kidney Disease
Conditions
Keywords
Kidney Disease, Albuminuria, Glomerular filtration rate, Volume status, Bioimpedance analysis
Brief summary
ABSTRACT Background: It is well recognized that excess dietary salt intake plays a major role in the development of hypertension. Chronic Kidney Disease (CKD) is associated with excess salt and water retention (excess volume) which is associated with hypertension. Hypotheses: Hypothesis 1: Dietary salt restriction will improve volume status in subjects with CKD stages 3-4 as assessed by Bioelectrical Impedance Analysis (BIA). Hypothesis 2: Dietary salt restriction will result in improved blood pressure control in patients with CKD stages 3-4. Hypothesis 3: Dietary salt restriction will decrease albuminuria in patients with CKD stages 3-4. Patients and Trial Design: This randomized crossover pilot study is designed to assess the effect of salt restriction on volume status in patients with CKD stages 3 and 4. Subjects will be randomized to a treatment order: (1) 4 weeks of salt restriction of \<85 mmol sodium per day, a 2 week washout period, and 4 weeks of usual salt diet, OR (2) 4 weeks of usual diet, 2 weeks washout, and 4 weeks of salt restriction. Patients will receive dietary counseling in person at each study visit and at weekly intervals by phone calls from study dieticians. At weeks 0, 4, 6 and 10, patients will undergo assessments for (i) physical examination with assessments for weight, blood pressure, pulse, anthropometrics and a standardized clinical assessment of volume status. (ii) volume status using bioelectrical impedance analysis (BIA) (iii) 24-hour urine testing for, albumin, creatinine and aldosterone Every 2 weeks throughout the study, a 24-hour urine sodium will be measured for compliance, and serum electrolytes will be assessed for safety. Data Analysis: BIA measurements in the low salt group will be compared with the regular diet group using the standard linear model analysis for 2x2 crossover trials. Additionally, 24-hour ambulatory and static blood pressure and 24-hour urine aldosterone levels will be compared between the two groups. Future Implications: A significant reduction in the degree of volume expansion (as assessed by BIA) and blood pressure as a result of a salt restricted diet would have implications for renal and cardiovascular protection and would warrant confirmation by a larger randomized trial.
Interventions
DIETARY_SUPPLEMENTLow Salt Diet
Dietary sodium restriction of ≤2.0 g/day or ≤ 85 mmol/day
DIETARY_SUPPLEMENTUsual Salt Diet
Usual salt intake (approximately \>180-200 mmol/day in the average American diet).
Sponsors
Renal Research Institute
University of Michigan
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
Individuals eligible to participate in this study must meet all of the following criteria: * Willing and able to provide written, signed informed consent after the nature of the study has been explained, and prior to any research-related procedures. * Age ≥ 18 years and ≤ 85 years. * Willing and able to comply with all study procedures. * Patients with eGFR of 20 to 60 ml/min/173m2 by the abbreviated (4-variable) MDRD equation and a relatively stable clinical course. * Sitting systolic blood pressure ≥ 100 mmHg prior to study entry (to exclude people at risk from hypotension from dietary salt reduction).
Exclusion criteria
Individuals who meet any of the following
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Primary Outcome: Change in volume status (intracellular, extracellular volume, and total body water) as measured by BIA using both whole body and segmental techniques | 12 Weeks |
Countries
United States
Outcome results
None listed