NCT05766774

Brief Summary

The goal of this study is to determine the extent to which excess dietary sugars serve as a precipitating factor in glucose intolerance in adults with cystic fibrosis (CF), a population at especially high risk for a unique form of diabetes (CF-related diabetes, CFRD) and with standard-of-care dietary recommendations (high-calorie, high-fat) that conflict with recommendations for other forms of diabetes. This trial will investigate if the typical high-sugar, high-fat CF diet plays a role in diabetes risk and visceral fat accumulation in people with CF. A total of 30 participants will get a low-added sugar, high-fat diet and the other 30 will get a standard CF diet with no sugar restrictions. Participants will be randomized to the diet group they are assigned. All foods will be provided for 8 weeks.

Trial Health

77
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
60

participants targeted

Target at P25-P50 for not_applicable

Timeline
25mo left

Started Jun 2023

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress58%
Jun 2023Jun 2028

First Submitted

Initial submission to the registry

February 21, 2023

Completed
20 days until next milestone

First Posted

Study publicly available on registry

March 13, 2023

Completed
4 months until next milestone

Study Start

First participant enrolled

June 28, 2023

Completed
4.9 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

June 1, 2028

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

June 1, 2028

Last Updated

April 6, 2025

Status Verified

April 1, 2025

Enrollment Period

4.9 years

First QC Date

February 21, 2023

Last Update Submit

April 3, 2025

Conditions

Outcome Measures

Primary Outcomes (4)

  • Change in acute insulin response to arginine (AIRarg) from baseline

    Participants will undergo a Glucose-Potentiated Arginine Stimulation (GPA) Test after a 10-12 hour overnight fast to measure acute insulin (AIRarg) responses during a 230 and 340 mg/dl glucose clamp. This test will measure changes in beta cell secretory capacity.

    Baseline and 8 weeks post intervention

  • Change in acute C-peptide (ACRarg) from baseline

    Participants will undergo a Glucose-Potentiated Arginine Stimulation (GPA) Test after a 10-12 hour overnight fast to measure acute C-peptide (ACRarg) responses during a 230 and 340 mg/dl glucose clamp. This test will measure changes in beta cell secretory capacity.

    Baseline and 8 weeks post intervention

  • Change in visceral adipose tissue from baseline

    Dual energy X-ray absorptiometry (DEXA)-derived measurement of visceral adipose tissue (VAT) will be assessed with a GE Lunar iDXA machine. This will enable assessment of changes in body composition over the study.

    Baseline and 8 weeks post intervention

  • Change in fasted plasma Eh[CySS] from baseline

    Change in plasma Cysteine/Cystine Redox Potential (Eh\[CySS\]) will be measured.

    Baseline and 8 weeks post intervention

Secondary Outcomes (3)

  • Change in Gastrointestinal Symptom Rating Scale (GSRS) scale

    Baseline and 8 weeks post intervention

  • Change in hepatic and pancreatic fat volume

    Baseline and 8 weeks post intervention

  • Change in fasted plasma Eh[GSSG]

    Baseline and 8 weeks post intervention

Study Arms (2)

Low-added sugar, high-fat diet Arm

EXPERIMENTAL

Patients will receive a low-added sugar, high-fat diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation.Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Other: Low-added sugar, high-fat diet

Typical CF diet Arm

ACTIVE COMPARATOR

Patients will receive a high-added sugar, high-fat CF diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation. Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Other: High-added sugar, high-fat CF diet

Interventions

Consist of \<5% kcal from added sugars as recommended by the American Heart Association, and the glycemic index will be 45 or lower (25% lower than typical CF diet). The macronutrient composition of both study diets will reflect the general CF recommendations for macronutrients: 35-40% of total kcal from fat and 15-20% total kcal from protein.

Low-added sugar, high-fat diet Arm

Consist of ≥13% kcal from added sugars and the glycemic index will be \>60. The macronutrient composition of both study diets will reflect the general CF recommendations for macronutrients: 35-40% of total kcal from fat and 15-20% total kcal from protein.

Also known as: Typical CF diet
Typical CF diet Arm

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Confirmed CF diagnosis
  • Ages 18 years and older
  • Baseline estimated daily total added sugar intake \>16 tsp, as estimated from the Dietary Screener Questionnaire (DSQ).

You may not qualify if:

  • Nocturnal tube feeds
  • BMI \<18.5 kg/m2
  • Life expectancy \< 12 months
  • Confirmed diagnosis of CFRD
  • Screening OGTT showing fasting hyperglycemia (≥126 mg/dL)
  • Chronic steroid use
  • Current pregnancy or lactation
  • Inability/unwillingness to consume the majority of foods on the menu during the study period
  • MRI-incompatible metal that cannot be removed for testing
  • Uncontrolled exocrine pancreatic insufficiency/malabsorption
  • Clinically instability, defined as no changes in medical regimen (including medications and pulmonary exacerbations) for at least 21 days prior to study visit
  • Initiation of CFTR modulator within previous 8 weeks OR unstable changes in weight and lung function due to CFTR modulator use
  • Actively trying to gain or lose weight
  • Any food allergies or intolerances that cannot be accommodated
  • Any medical condition deemed by the a study physician or PI that may preclude completion of the study or interfere with primary end points.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Emory University Hospital

Atlanta, Georgia, 30322, United States

RECRUITING

Related Publications (1)

  • Zaveri S, Stecenko A, Hunt WR, Goss A, Sharma P, Hartman TJ, Easley K, Chandler JD, Burley TM, Driggers C, Ciccarella A, Zhou H, Narlow K, Ziegler TR, Daley T, Vellanki P, Alvarez J. Low-added sugar dietary intervention study to mitigate glucose intolerance and improve body composition in adults with cystic fibrosis: a protocol of a double-blind, randomised study. BMJ Open. 2024 Dec 26;14(12):e092503. doi: 10.1136/bmjopen-2024-092503.

MeSH Terms

Conditions

Cystic Fibrosis

Interventions

Diet, High-Fat

Condition Hierarchy (Ancestors)

Pancreatic DiseasesDigestive System DiseasesLung DiseasesRespiratory Tract DiseasesGenetic Diseases, InbornCongenital, Hereditary, and Neonatal Diseases and AbnormalitiesInfant, Newborn, Diseases

Intervention Hierarchy (Ancestors)

DietNutritional Physiological PhenomenaDiet, Food, and NutritionPhysiological Phenomena

Study Officials

  • Jessica A Alvarez, PhD, RD

    Emory University

    PRINCIPAL INVESTIGATOR

Central Study Contacts

Jessica A Alvarez, PhD, RD

CONTACT

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
TRIPLE
Who Masked
PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
Masking Details
The study team, including the investigators, statistician, and coordinator, will be blinded to diet allocation throughout. All major assessments and assays will be performed by individuals who will be blinded to the diet. Participants will not be informed of their allocated diet.
Purpose
PREVENTION
Intervention Model
PARALLEL
Model Details: A double-blind, randomized, parallel-group design clinical trial.
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Associate Professor

Study Record Dates

First Submitted

February 21, 2023

First Posted

March 13, 2023

Study Start

June 28, 2023

Primary Completion (Estimated)

June 1, 2028

Study Completion (Estimated)

June 1, 2028

Last Updated

April 6, 2025

Record last verified: 2025-04

Data Sharing

IPD Sharing
Will share

Actual clinical study data in raw and summary form, with protected health information removed, as well as access to the study database, will be available for reference of qualified professional colleagues and auditors up to 10 years after study publication. With appropriate subject informed consent, clinical and research data obtained from this study will be deposited into the Georgia CF Data Warehouse of the NDDK P30-supported Georgia Cystic Fibrosis Clinical and Translational Core Center.

Shared Documents
STUDY PROTOCOL
Time Frame
After final publication date
Access Criteria
Qualified researchers for analyses of original study endpoints not pre-specified as primary, secondary, or exploratory that contact the investigators.

Locations