The Diet Gout Trial (DIGO)

Dietary Approaches to Stop Hypertension (DASH) Diet Effects on Serum Uric Acid (SUA) in Adults With Hyperuricemia and Gout

Unhealthy diet has long been associated with high uric acid levels and gout. The DASH diet may lower uric acid levels. This study will examine the effects of the DASH diet on uric acid in adults with a history of gout.

Study Overview

• Status: Completed
• Conditions: Hyperuricemia; Gout
• Intervention / Treatment: Other: Subsidy for food purchases and dietitian education

Detailed Description

The public health burden of gout is substantial. Several lines of evidence suggest that a DASH diet might lower uric acid. However, there are no trials of the DASH diet in adults with gout. This trial is a cross-over study of the effects of a DASH-like diet on uric acid in adults with gout and hyperuricemia, who are not taking urate-lowering therapy.

Perpetuated by the "Western" lifestyle and resulting obesity epidemic, the prevalence of gout has increased over the past few decades to 3.9% of US adults (8.3 million individuals). This prevalence increases with age to 9.3% of US adults over 60 years (4.7 million).

Participants will be community-dwelling adults, aged 18+ with a baseline serum uric acid level of 7 mg/dL, who have a self-reported history of gout and are not taking urate lowering medications (e.g. allopurinol, febuxostat, probenecid).

This trial is comprised of two study periods: (1) a dietitian-directed diet (DD) or (2) self-directed usual diet (SD). Each period lasts 4 weeks. All participants will participate in both periods, but half will undergo the dietitian-directed diet first while the other half will undergo the self-directed diet first. During the dietitian-directed diet, participants will receive $105/week of foods in a pattern that conforms to the DASH diet. The DASH diet emphasizes fruit, vegetables, lean meat, low fat dairy, and high fiber, while restricting red meat, sweets, and sugary beverages. During the self-directed diet, participants will be asked to eat their typical diet outside of the study. Investigators anticipate 40 participants in this study.

The primary outcome is uric acid. Secondary outcomes of this study include: body mass index, systolic and diastolic blood pressure, fasting cholesterol, and fasting blood glucose. Both primary and secondary outcomes will be measured 3 times: (1) before the study begins (baseline), (2) after period 1 (at 4 weeks), and (3) after period 2 (at 8 weeks). Patient-reported outcomes, dietary compliance, and urine electrolytes will be assessed throughout the study as well.

The primary comparison will be serum uric acid concentrations measured after the 4-week dietitian-directed diet versus uric acid concentrations measured after the 4-week self-directed diet (DD vs. SD). Comparisons will be made within person using generalized estimating equations (GEE) with and without adjustment for baseline uric acid concentration. Investigators will use GEE models for secondary outcomes as well.

• Study Type: Interventional
• Enrollment (Actual): 43
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Woodlawn, Maryland, United States, 21207
      • Johns Hopkins ProHealth Research Clinic
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Massachusetts General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

Age > 18-100 years

Self-reported gout diagnosis

Serum Uric Acid > 7 mg/dL

Exclusion Criteria:

Recent or planned changes to urate lowering therapies (e.g. allopurinol, febuxostat, probenecid)

Recent or planned changes to hypertension, lipid, or diabetes medications

Patients with hyperkalemia (>5 mmol/L)

Chronic kidney disease (GFR < 30 cc/min), kidney transplant, dialysis

Gastro-intestinal conditions (e.g. history of gastric bypass surgery, active inflammatory bowel disease, malabsorption, or major GI resection)

Active cancer treatment (e.g. radiation or chemotherapy)

Diagnosis of any of the following in the past 6 months: heart attack, heart failure, angina, coronary bypass or angioplasty, or Chronic Obstructive Pulmonary Disease (COPD)

Alcohol use over 14 drinks per week

Inability to give informed consent

Active use of warfarin, insulin, or chronic steroids (like prednisone)

Terminal or mental illness

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dietitian-Directed Diet; Participants will be provided $105/week ($15/day) to purchase foods in servings that correspond to the DASH diet and thus include fruits, vegetables, lean meat, low fat dairy, and high fiber foods. Participants will also be asked to restrict red meat, sweets, and sugary beverages during this intervention period. A dietitian will help participants order foods from a digital supermarket. Foods will be delivered to the Johns Hopkins ProHealth Research Clinic for weekly pick-up. This study period will last 4 weeks.	Other: Subsidy for food purchases and dietitian education; $105/wk of DASH-like foods over 4 weeks purchased with the help of a dietitian in a proportion that reflects the DASH diet.
No Intervention: Self-Directed Diet; Participants will be asked to consume their typical diet for 4 weeks. There will be no subsidy during this period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Uric Acid Level	Measured in serum	Baseline
Uric Acid Level	Measured in serum	At 4-weeks
Uric Acid Level	Measured in serum	At 8-weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Systolic Blood Pressure (mm Hg)		Baseline, 4-weeks, 8-weeks
Diastolic Blood Pressure (mm Hg)		At baseline, 4-weeks, 8-weeks
Fasting Blood Glucose (mg/dL)	Measured in serum	Baseline, 4-weeks, 8-weeks
Low Density Lipoprotein Cholesterol (mg/dL)	Measured in serum	Baseline, 4-weeks, 8-weeks
Body Mass Index (kg/m^2)	Derived from baseline height, and serial weight measurements	Baseline, 4-weeks, 8-weeks

Collaborators and Investigators

• Sponsor: Johns Hopkins University
• Collaborators: Harvard Medical School (HMS and HSDM); Massachusetts General Hospital; Beth Israel Deaconess Medical Center; Rheumatology Research Foundation
• Investigators: Principal Investigator: Edgar Miller, Johns Hopkins University

Publications and helpful links

General Publications

• Ghazi L, Drawz PE, Pajewski NM, Juraschek SP. The Association of Orthostatic Hypotension With Ambulatory Blood Pressure Phenotypes in SPRINT. Am J Hypertens. 2021 May 22;34(5):511-520. doi: 10.1093/ajh/hpaa184.
• Miller HN, Charleston J, Wu B, Gleason K, White K, Dennison Himmelfarb CR, Ford DE, Plante TB, Gelber AC, Appel LJ, Miller ER 3rd, Juraschek SP. Use of electronic recruitment methods in a clinical trial of adults with gout. Clin Trials. 2021 Feb;18(1):92-103. doi: 10.1177/1740774520956969. Epub 2020 Sep 15.

Helpful Links

• Main results paper

Study record dates

Study Major Dates

• Study Start (Actual): August 7, 2018
• Primary Completion (Actual): July 23, 2019
• Study Completion (Actual): July 23, 2019

Study Registration Dates

• First Submitted: June 14, 2018
• First Submitted That Met QC Criteria: June 14, 2018
• First Posted (Actual): June 26, 2018

Study Record Updates

• Last Update Posted (Actual): March 30, 2021
• Last Update Submitted That Met QC Criteria: March 3, 2021
• Last Verified: November 1, 2019

More Information

Terms related to this study

• Keywords: Arthritis; Cholesterol; Fiber; Nutrition; Lipid; Diet; Blood pressure; Gout; Hyperuricemia; Uric acid; Trial; BMI; Fruit; Weight; Glucose; Potassium; DASH; Body mass index; Vegetable; Low fat dairy; Lean meat
• Additional Relevant MeSH Terms: Pathologic Processes; Metabolic Diseases; Genetic Diseases, Inborn; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Arthritis; Metabolism, Inborn Errors; Crystal Arthropathies; Purine-Pyrimidine Metabolism, Inborn Errors; Hyperuricemia; Gout
• Other Study ID Numbers: IRB00153409

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No