Open Label, Randomized, Multicenter, Comparative Effectiveness Trial of Specific Carbohydrate and Mediterranean Diets to Induce Remission in Patients with Crohn's Disease (DINE-CD), United States, 2017-2020 (ICPSR 38590)

Time Period(s) View help for Time Period(s)

Date of Collection View help for Date of Collection

Study Purpose View help for Study Purpose

The purpose of the study was to compare the effectiveness of the Specific Carbohydrate Diet (SCD) and a Mediterranean style diet (MSD) in inducing symptomatic and clinical remission in patients with mild to moderate Crohn's disease.

Study Design View help for Study Design

A parallel group, randomized trial was conducted in 33 sites across the United States. Enrollment in the trial occurred between September 2017 and October 2019. Potential participants were identified through physician referral, chart review, and the Crohn's and Colitis Foundation of America (CCFA) Partners Patient-Powered Research Network (PPRN), and were referred to a participating center in their region for screening and enrollment. If eligible, baseline data with blood sample were collected in-person following screening and consent procedures. Following nominal eligibility designation, participants were required to complete five to seven days of daily online surveys recording symptoms as measured by the short Crohn's Disease Activity Index (sCDAI) and submit a baseline stool sample in order to be randomized to a treatment group. If accessible, results of the individual's most recent colonoscopy prior to randomization were also collected.

To randomize the sample into treatment groups, a computer-generated randomization order stratified by whether the participant was currently receiving therapy with a biologic drug was used to allocate participants in a 1:1 ratio to either the MSD or SCD using random block sizes of 2 and 4. Neither the research team nor the participants were aware of the diet to be assigned next. The SCD was designated the intervention diet, while the MSD was considered the reference or control diet.

During the first six weeks of the trial, participants received weekly delivery of prepared meals (breakfast, lunch, dinner, and two snacks per day, minimum 2500 calories) consistent with their assigned diet. During weeks six through twelve, participants were asked to adhere to their assigned diet by preparing or purchasing their own meals and snacks, and were provided with detailed meal planning guidance and recipes.

Participants completed daily online surveys to determine sCDAI scores from baseline to week twelve. Diet satisfaction surveys were also completed at weeks three, six, nine, and twelve. In-person visits were completed to evaluate for symptom remission at week six and week twelve, and a final stool sample was submitted. Participants were withdrawn from the study if they experienced worsening symptoms that required a change in their Crohn's disease treatment.

Sample View help for Sample

Adults with mild to moderate symptoms of Crohn's disease (sCDAI score between 175 and 400) who had internet access were eligible. Individuals were excluded from the study if they were pregnant, hospitalized patients, had used the SCD within four weeks of screening, or were taking certain medications prior to screening.

460 individuals were screened for participation, with 263 failing to meet eligibility criteria and 3 electing not to participate after meeting criteria but prior to diet assignment. 194 participants were randomly assigned to treatment groups, 93 to the MSD and 101 to the SCD. 33 participants withdrew from the study before week 6, and 37 withdrew between weeks 6 and 12. Overall, 63% of participants were women, 91% were White, and 4% were of Hispanic ethnicity.

Time Method View help for Time Method

Universe View help for Universe

Adults with Crohn's disease having mild to moderate symptoms at the time of enrollment.

Unit(s) of Observation View help for Unit(s) of Observation

Data Type(s) View help for Data Type(s)

Mode of Data Collection View help for Mode of Data Collection

Description of Variables View help for Description of Variables

The primary outcome variable was symptomatic remission at week six, defined as a sCDAI score of less than 150 with no new Crohn's disease medications started or increased. A secondary outcome was a resolution of inflammation, measured by fecal calprotectin (FCP) response and C-reactive protein (CRP) response.

Additional measures included vital signs (at in-person visits), medical history, diet history, prior and current medications, quality of life markers (fatigue, social isolation, pain interference, and sleep disturbance), inflammatory bowel disease symptoms, arthritis symptoms, physical functionality, diet adherence with 24-hour dietary recall, any adverse events that occurred during the course of the study, and patient demographics (age, sex, race, ethnicity).

Presence of Common Scales View help for Presence of Common Scales

Short Crohn's Disease Activity Index (sCDAI) and Crohn's Disease Activity Index (CDAI)

Inflammatory Bowel Disease Questionnaire (IBDQ)

Harvey-Bradshaw Index

Bath Ankylosing Spondylitis Functional Index (BAS-FI)

Routine Assessment of Patient Index Data (RAPID-3)

Rheumatoid Arthritis Disease Activity Index (RADAI)

Patient-Reported Outcomes Measurement Information System (PROMIS)

Original Release Date View help for Original Release Date

2023-02-02

Version History View help for Version History