Dietary Salt in Rheumatoid Arthritis

Vanderbilt University Medical Center18 enrolled

Overview

In this study investigators propose to address the following hypotheses: 1) Reduction in dietary sodium will decrease inflammation in patients with rheumatoid arthritis (RA). 2) Reduction in dietary sodium will decrease blood pressure in patients with RA. 3) Reduction in dietary sodium will decrease tissue sodium in patients with RA.

The study is a random-order, 2 period crossover study with washout. Participants will be randomly assigned to be on the high-sodium diet (200mmol/24hours x 8weeks) or low-sodium diet (50mmol/24hours x 8 weeks ) with crossover separated by 4-week washout period. Investigators will allow a 7-day window on the diet (i.e., to facilitate scheduling the diet can be between 7-9 weeks), and investigators will allow a 1-week window for the washout (i.e., washout can be 3-5 weeks). Investigators will measure changes in inflammation (as measured by DAS28 (using tender and swollen joint count, disease activity and sedimentation rate)), blood pressure measured over a 24 hour period, and tissue sodium (using Magnetic Resonance Imaging (MRI)). If a relatively simple dietary modification has a clinically important effect on inflammation and blood pressure regulation in vivo in patients with RA, this will have far-reaching implications for the treatment of RA and prevention of Cardiovascular disease in this population.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

OTHER

Masking

DOUBLE

Enrollment

Conditions

Rheumatoid Arthritis

Interventions

saltOTHER

Participants will randomly eat a high salt diet for 8 weeks and a low salt diet for 8 weeks

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Male and female patients older than 18 years who are willing to participate. 2. Satisfy the ACR criteria for the diagnosis of RA. 3. Have stable disease activity as evidenced by no clinically meaningful change in immunomodulating or corticosteroid therapy in the past 1 month. 4. Have moderate disease activity as reflected by a minimum of 3 swollen and tender joints. Exclusion Criteria: 1. Pregnancy 2. Receiving dialysis 3. Organ or bone marrow transplant 4. Taking diuretics, uncontrolled hypertension (\>160/100 mmHg), or cardiac failure requiring treatment. 5. Severe edema (as judged by the investigator) 6. Diabetes mellitus treated with an insulin pump 7. Major surgery within the previous 3 months 8. Severe co-morbid conditions such as active cancer likely to compromise study participation 9. Unwillingness, or other inability, to cooperate 10. Contraindication to MRI 11. Presence of a condition that could make 24-hour blood pressure monitoring difficult: atrial fibrillation, inability to operate machine, receiving anticoagulants, presence of a condition that in the opinion of the investigator may be exacerbated by blood pressure cuff inflation (e.g., lymphedema).

Locations (1)

Vanderbilt University Medical Center

Nashville, Tennessee, United States

Outcomes

Primary Outcomes

Change in Tissue Sodium

Investigators will measure change in tissue (skin) sodium using 3.0 T MRI equipped with a 23Na coil.

Time frame: 2 scans, one at end of week 8, and one at end of week 20

Secondary Outcomes

Change in DAS28-CRP

DAS28-CRP score is a disease activity score based on 28 joints and C-reactive protein. Lower is better. Range= 0.96 units to 10. DAS28-CRP = 0.56 x sqrt(tender joint count) + 0.28 x sqrt(swollen joint count) + 0.36 x ln(C-reactive protein + 1) + 0.014 x global health score + 0.96

Time frame: Measured at beginning and end of each diet period at weeks 0, 8, and 12, 20

Change in Blood Pressure

Investigators will measure change in systolic blood pressure.

Time frame: Measured at beginning and end of each diet period at weeks 0,8 and 12, 20

Data from ClinicalTrials.gov

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