Lowering Salt Intake in Chronic Kidney Disease: A Pilot Randomized Crossover Trial (BIA)

• ClinicalTrials.gov Identifier: NCT00974636
• Recruitment Status: Completed
• First Posted: September 10, 2009
• Last Update Posted: August 5, 2015
• Sponsor: University of Michigan
• Collaborator: Renal Research Institute
• Information provided by (Responsible Party): Rajiv Saran, University of Michigan

Tracking Information

• First Submitted Date: September 9, 2009
• First Posted Date: September 10, 2009
• Last Update Posted Date: August 5, 2015
• Study Start Date: May 2009
• Actual Primary Completion Date: February 2013 (Final data collection date for primary outcome measure)
• Current Primary Outcome Measures (submitted: September 9, 2009): Primary Outcome: Change in volume status (intracellular, extracellular volume, and total body water) as measured by BIA using both whole body and segmental techniques [ Time Frame: 12 Weeks ]
• Original Primary Outcome Measures: Same as current
• Current Secondary Outcome Measures: Not Provided
• Original Secondary Outcome Measures: Not Provided
• Current Other Pre-specified Outcome Measures: Not Provided
• Original Other Pre-specified Outcome Measures: Not Provided

Descriptive Information

• Brief Title: Lowering Salt Intake in Chronic Kidney Disease: A Pilot Randomized Crossover Trial
• Official Title: Lowering Salt Intake in Chronic Kidney Disease: A Pilot Randomized Crossover Trial

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.

• Detailed Description: Not Provided
• Study Type: Interventional
• Study Phase: Not Applicable
• Study Design: Allocation: Randomized; Intervention Model: Crossover Assignment; Masking: None (Open Label)
• Condition: Kidney Disease

Intervention

• Dietary Supplement: Low Salt Diet
  Dietary sodium restriction of ≤2.0 g/day or ≤ 85 mmol/day
  Other Name: Low salt diet, CKD, Bioimpedance analysis (BIA)
• Dietary Supplement: Usual Salt Diet
  Usual salt intake (approximately >180-200 mmol/day in the average American diet).

Study Arms

• Experimental: Low Salt Diet
  Dietary sodium restriction of ≤2.0 g/day or ≤ 85 mmol/day for two weeks
  Intervention: Dietary Supplement: Low Salt Diet
• Placebo Comparator: Ususal Salt Diet
  Usual salt intake (approximately >180-200 mmol/day in the average American diet).
  Intervention: Dietary Supplement: Usual Salt Diet

• Publications *: McMahon EJ, Campbell KL, Bauer JD, Mudge DW, Kelly JT. Altered dietary salt intake for people with chronic kidney disease. Cochrane Database Syst Rev. 2021 Jun 24;6(6):CD010070. doi: 10.1002/14651858.CD010070.pub3.

Recruitment Information

• Recruitment Status: Completed
• Actual Enrollment (submitted: January 7, 2013): 35
• Original Estimated Enrollment (submitted: September 9, 2009): 75
• Actual Study Completion Date: May 2013
• Actual Primary Completion Date: February 2013 (Final data collection date for primary outcome measure)

Eligibility Criteria

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 exclusion criteria will not be eligible to participate in the study:

• Recent acute illness (≤1 month). Minor ailments such as a recovered common cold or allergic rhinitis would not be considered as exclusion criteria but would be left to the site PI's discretion.
• Recent hospitalization (≤1 month) unless clearly for a minor elective procedure unlikely to interfere with BIA measurements. The final decision will be left to the site PI's discretion.
• Any psychological condition (including alcoholism) that could interfere with the patient's ability to comply with the study protocol.
• Subjects with baseline 24-hour urinary sodium excretion ≤100 mmol/day.
• Amputation of a limb other than fingers or toes.
• Pacemaker, defibrillator, implantable pump, artificial joint, pins, plates or other types of metal objects in the body (other than dental fillings).
• Coronary stents or metal suture material in the heart.
• Use of any investigational product or investigational medical device within 30 days prior to screening, or requirement for any investigational agent prior to completion of all scheduled study assessments.
• Weight over 300 pounds (limitation for examination table).
• Pregnancy or lactation.
• Patients with kidney diseases known to be associated with salt wasting (see above).
• Patients with atrial fibrillation as ambulatory blood pressure measurements may not be accurate in this setting.
• Any condition that, in the view of the PI, places the subject at high risk of poor treatment compliance or of not completing the study.

Sex/Gender

• Sexes Eligible for Study: All

• Ages: 18 Years to 85 Years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: United States

Administrative Information

• NCT Number: NCT00974636
• Other Study ID Numbers: HUM00016384
• Has Data Monitoring Committee: No
• U.S. FDA-regulated Product: Not Provided
• IPD Sharing Statement: Not Provided
• Current Responsible Party: Rajiv Saran, University of Michigan
• Original Responsible Party: Rajiv Saran, MD, MS, MRCP, Associate Professor, Div. of Nephrology, Dept. of Int. Med, Univ. Of Michigan, Ann Arbor, MI
• Current Study Sponsor: University of Michigan
• Original Study Sponsor: Same as current
• Collaborators: Renal Research Institute

Investigators

• Principal Investigator: Rajiv Saran, MD; University of Michigan

• PRS Account: University of Michigan
• Verification Date: August 2015