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

NCT00974636 | Completed

• 1 other identifier: HUM00016384
• Study Type: interventional
• Target: 35
• Locations: 1 country
• Sites: 1

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.

Conditions

Kidney Disease

Keywords

Kidney Disease; Albuminuria; Glomerular filtration rate; Volume status; Bioimpedance analysis

Outcome Measures

Primary Outcomes (1)

• 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

Study Arms (2)

Low Salt Diet

EXPERIMENTAL

Dietary sodium restriction of ≤2.0 g/day or ≤ 85 mmol/day for two weeks

Dietary Supplement: Low Salt Diet

Ususal Salt Diet

PLACEBO COMPARATOR

Usual salt intake (approximately \>180-200 mmol/day in the average American diet).

Dietary Supplement: Usual Salt Diet

Interventions

Low Salt Diet DIETARY_SUPPLEMENT

Dietary sodium restriction of ≤2.0 g/day or ≤ 85 mmol/day

Also known as: Low salt diet, CKD, Bioimpedance analysis (BIA)

Low Salt Diet

Usual Salt Diet DIETARY_SUPPLEMENT

Usual salt intake (approximately \>180-200 mmol/day in the average American diet).

Ususal Salt Diet

Eligibility Criteria

• Age: 18 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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).

You may not qualify if:

• 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.

Sponsors & Collaborators

• University of Michigan: lead
• Renal Research Institute: collaborator

Study Sites (1)

University of North Carolina

Chapel Hill, North Carolina, 27599, United States

Location

Related Publications (1)

• 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.

  PMID: 34164803 DERIVED

MeSH Terms

Conditions

Kidney Diseases; Albuminuria

Interventions

Diet, Sodium-Restricted

Condition Hierarchy (Ancestors)

Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Proteinuria; Urination Disorders; Urological Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Officials

• Rajiv Saran, MD

  University of Michigan

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: MD, MS, MRCP, Associate Professor

Study Record Dates

• First Submitted: September 9, 2009
• First Posted: September 10, 2009
• Study Start: May 1, 2009
• Primary Completion: February 1, 2013
• Study Completion: May 1, 2013
• Last Updated: August 5, 2015

Record last verified: 2015-08

Locations

US (1)