The Effects of a Low Glycemic Load Diet on Dysglycemia and Body Composition in Adults With Cystic Fibrosis-Related Diabetes
- Conditions
- Cystic Fibrosis-related DiabetesCystic FibrosisCystic Fibrosis With Intestinal Manifestations
- Interventions
- Behavioral: Low Glycemic Load Diet
- Registration Number
- NCT05723445
- Lead Sponsor
- Rhode Island Hospital
- Brief Summary
This study will evalute the effect of a low glycemic load (LGL diet on dysglycemia, insulin requirements, DXA-derived body composition, gastrointestinal symptoms and quality of life measures in adults with cystic fibrosis-related diabetes (CFRD). We will use continuous glucose monitors (CGM) to assess the LGL diet both in a controlled setting (via a meal delivery company) and in free-living conditions.
- Detailed Description
Maintenance of a healthy body mass index (BMI) is a well-established marker of improved morbidity and mortality in patients with cystic fibrosis (CF). To achieve and maintain adequate weight, patients with CF are encouraged to consume a caloric intake of 120-150% of the dietary reference intake (DRI) for the typical healthy adult. However, dietary recommendations for children and adults with CF are based entirely on consensus and expert opinion. High carbohydrate intake is typical for patients with CF, but this may lead to multiple complications including post-prandial hyperglycemia, increased inflammation, and abnormal GI motility and may predispose to obesity and metabolic syndrome. Dietary changes are a commonly used treatment approach for CF-related diabetes (CFRD), despite the fact that there are no data establishing whether dietary interventions are helpful in preventing and/or treating CFRD. Particularly as patients with CF live longer with highly effective modulator therapy and as the prevalence of cardiovascular and metabolic disease increases in this population, it is crucial to understand the effects of dietary composition on short and long-term endocrine, GI, and pulmonary outcomes.
In patients with both type 1 and type 2 diabetes mellitus, a low glycemic load (LGL) diet has been shown to improve glycemic variability, A1c level, insulin sensitivity, and quality of life without increasing hypoglycemic events. Significant glycemic variability is associated with increased markers of inflammation in adolescents with T1DM, possibly serving as a mechanistic link to the development of cardiovascular disease. Particularly as rates of obesity and cardiovascular disease continue to increase, this diet may be particularly useful in patients with CF, altered glucose homeostasis, and/or obesity. There are currently no prospective studies evaluating the impact of diet quality on glycemic control and body composition in patients with CF. The gold standard approach for assessing the safety and efficacy of dietary interventions is a food delivery study.
The investigators will conduct a prospective, open-label study in adults with CFRD to determine the effects of an LGL diet on dysglycemia and body composition. Participants will initially follow their standard diet for a 10-day run-in period. They will then transition to an LGL diet provided by a meal delivery company for 8 weeks. During this period, they will wear a continuous glucose monitor (CGM) for 2 10-day periods. Finally, participants will adhere to an LGL diet under free-living conditions with close nutritionist follow-up for a period of 4 months. Serum studies, DXA-body composition, anthropometric data, GI symptoms and quality of life measures will be obtained at baseline, after the meal-delivery phase and at study completion.
The investigators hypothesize that an LGL diet will result in improved CGM-derived measures of hyperglycemia, a decrease in insulin requirements, and reductions in fat-mass index on DXA analysis in adults with CFRD over an 8-week period during a meal delivery period. Furthermore, they hypothesize that these changes will be sustainable under free-living conditions during a 4-month period.
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 15
- 18 years and above
- Genetically confirmed diagnosis of CF
- Diagnosis of pancreatic insufficiency, requiring pancreatic enzyme replacement
- Criteria for CFRD:
A.) Most recent OGTT 2-hour glucose >200 mg/dL within the past two years, and/or; B.) HbA1c >6.5% in the past two years, and/or; C.) Current use of insulin
- FEV1 <50% predicted on most recent pulmonary function testing
- BMI <18 kg/m2
- Currently receiving enteral nutrition support via GT feeds
- Pregnancy, plan to become pregnant in the next 3-months, or sexually active without use of contraception
- Use of IV antibiotics or systemic supraphysiologic glucocorticoids for CF exacerbation within 1 month
- Started or stopped treatment with a CFTR modulator within 3 months of enrollment
- Currently adhering to an LGL or other carbohydrate-restricted diet (carbohydrate intake <30% of total daily caloric intake)
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SEQUENTIAL
- Arm && Interventions
Group Intervention Description Low Glycemic Load Diet Low Glycemic Load Diet Feeding study with dietary composition (approximately) 50% fat, 20% protein, 30% carbohydrate.
- Primary Outcome Measures
Name Time Method Change in percent time in target range 70-180 mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
- Secondary Outcome Measures
Name Time Method Change in percent time <70 mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in percent time <54 mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in percent body fat (%) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) DXA body composition measures
Change in CGM standard deviation (SD) Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in appendicular lean mass index (ALMI, lean mass kg/ height m^2) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) DXA body composition measures
Change in Patient Assessment of Gastrointestinal Symptoms (PAGI-Sym) questionnaire score Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Likert scale questionnaire with 20 items, each scored 0-5, total score ranging from 0-100 with higher scores related to worse outcomes
Change in erythrocyte sedimentation rate (ESR) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mm/hr
Change in CGM average glucose (AG) mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in CGM coefficient of variation (CV) Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in total daily dose of insulin (TDD) Baseline (weeks 1-2), visit 2 (post-meal delivery phase, weeks 2-10), visit 3 (post-free living conditions phase, weeks 11-26) Weekly emailed survey
Change in triglyceride level Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mg/dL
Change in percent time >180 mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in percent time >250 mg/dL Baseline, post-meal delivery phase (8 weeks), post-free-living conditions phase (4 months) Continuous glucose monitoring
Change in number of episodes of symptomatic hypoglycemia (average per week) Baseline (weeks 1-2), visit 2 (post-meal delivery phase, weeks 2-10), visit 3 (post-free living conditions phase, weeks 11-26)) Weekly emailed survey
Change fat-mass index (FMI, fat mass kg/ height m^2) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) DXA body composition measures
Change in Patient Assessment of Constipation (PAC) questionnaire score Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Likert scale questionnaire with 12 items, each scored 0-4, total score ranging from 0-48 with higher scores related to worse outcomes
Change in hemoglobin A1c Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in %
Change in total cholesterol Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mg/dL
Change in low-density lipoprotein (LDL) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mg/dL
Change in intestinal fatty acid binding protein (I-FABP) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in ng/mL
Change in body mass index (BMI, kg/m2) Baseline (weeks 1-2), visit 2 (post-meal delivery phase, weeks 2-10), visit 3 (post-free living conditions phase, weeks 11-26) Every other week emailed survey
Change in weight (kg) Baseline (weeks 1-2), visit 2 (post-meal delivery phase, weeks 2-10), visit 3 (post-free living conditions phase, weeks 11-26) Every other week emailed survey
Change in Cystic Fibrosis Questionnaire Revised (CFQ-R) score Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Likert scale questionnaire with 50 items, each scored 0-4, total score ranging from 0-100 with higher scores reflecting better outcomes
Change in Bristol stool chart data Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Chart depicting 7 types of stool patterns, ranging from constipation to diarrhea
Change in c-reactive protein (CRP) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mg/L
Change in high-density lipoprotein (HDL) Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Laboratory test, measured in mg/dL
Change in Diet Tolerability Questionnaire Baseline (week 1), visit 2 (post-meal delivery phase, week10), visit 3 (post-free living conditions phase, week 26) Likert scale questionnaire with 5 items, each scored 0-10, total score ranging from 0-50 with higher scores reflecting better diet tolerability
Trial Locations
- Locations (2)
Boston Children's Hospital
🇺🇸Boston, Massachusetts, United States
Rhode Island Hospital
🇺🇸Providence, Rhode Island, United States