Cystic Fibrosis, Cystic Fibrosis-related Diabetes, Cystic Fibrosis With Intestinal Manifestations
Conditions
Keywords
Cystic Fibrosis Related Diabetes, Low Glycemic Load, Continuous Glucose Monitoring
Brief summary
This pilot study will evaluate the safety and tolerability of a low glycemic load dietary intervention in adult patients with cystic fibrosis (CF) in a rigorous feeding study. Specific emphasis will be placed on changes in weight, body composition, and glycemic measures obtained via continuous glucose monitor (CGM) usage.
Detailed description
Non-pulmonary complications of cystic fibrosis (CF) are becoming increasingly prevalent with the changing landscape of CF care. CF related diabetes mellitus (CFRD) and CF related gastrointestinal (GI) complications have significant effects on morbidity and mortality. Treatment options are limited to insulin therapy for CFRD and symptom control for most GI complications. BMI is a well-established marker of morbidity and mortality in patients with CF. Many patients consume a high carbohydrate intake to meet their increase caloric needs, potentially leading to complications including post-prandial hyperglycemia, increased inflammation, and abnormal GI motility. Dietary recommendations for children and adults with CF are limited and based entirely on consensus and expert opinion. As patients with CF live longer with highly effective modulator therapy, it is important to understand the effects of dietary composition on short and long-term endocrine, GI, and pulmonary outcomes. The investigators will conduct a prospective, open-label pilot study in adults with CF and impaired glucose tolerance or indeterminate glycemia to establish the safety and tolerability of a low glycemic load (LGL) diet. Subjects will initially follow their standard diet for a 2-week run-in period, then transition to a LGL diet provided by a food delivery service for the remaining 8 weeks. The investigators will also investigate potential short-term outcomes of dietary carbohydrate manipulation, including glycemic variability measured by continuous glucose monitor (CGM), body composition via DXA, GI symptoms, and quality of life measures. The investigators hypothesize that a diet lower in carbohydrate content will be safe, tolerable, and associated with weight maintenance or gain, and that a LGL diet will result in decreased glycemic variability via CGM, improved GI symptoms, increased lean to fat mass ratio, and improved quality of life measures over an 8-week period.
Interventions
BEHAVIORALLow Glycemic Load Diet
Food delivery service will provide a low glycemic load diet for 8 weeks
Sponsors
Boston Children's Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Single dietary treatment arm with run-in period as a control
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
1. Diagnosis of CF 2. Diagnosis of pancreatic insufficiency, requiring pancreatic enzyme replacement 3. Oral glucose tolerance test within the past three years showing impaired glucose tolerance (2-hour glucose ≥140 mg/dL) or indeterminate glycemia (1-hour glucose ≥200), HbA1c 5.7-6.4% in the past one year, and/or or documented random glucose ≥200 in the past one year 4. BMI 21-25 kg/m2 5. 18 years and above
Exclusion criteria
1. Current use of insulin 2. Most recent HbA1c ≥6.5% 3. History of solid organ transplant or currently listed for solid organ transplant 4. FEV1 \<50% predicted on most recent pulmonary function testing 5. Currently receiving enteral nutrition support 6. Current or anticipated pregnancy in the next 1 year 7. Hospitalization for CF exacerbation within 1 month of enrollment 8. Started or stopped treatment with Trikafta or other CFTR modulator within 3 months of enrollment 9. Currently adhering to a low glycemic index or other carbohydrate restricted diet
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Patient reported tolerability of dietary intervention, Likert scale | Single measurement at 10 weeks after diet completion | Single Likert scale question of overall diet tolerability, ranging from 1 (intolerable) to 10 (completely tolerable) |
| Change in weight from baseline and 10 weeks | Baseline and 10 weeks | Anthropometric measure |
| Change in percent time <54 mg/dL | Baseline and 10 weeks | Continuous glucose monitoring |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in CGM standard deviation (SD) | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in CGM coefficient of variation (CV) | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in percent time less than 50 mg/dL on CGM | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in percent time less than 70 mg/dL on CGM | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in percent time 70-180 mg/dL on CGM | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in percent time greater than 180 mg/dL on CGM | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in percent time greater than >250 mg/dL on CGM | Baseline to 10 weeks | Continuous glucose monitoring |
| Number of episodes of symptomatic hypoglycemia | Baseline and 10 weeks | Survey |
| Change in percent time >140 mg/dL | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in Patient Assessment of Constipation (PAC) questionnaire score | Baseline and 10 weeks | Likert scale questionnaire with 12 items, each item scored 0-4, total score ranging from 0-48 with higher scores related to worse outcomes |
| Change in Patient Assessment of Gastrointestinal Symptom (PAGI-SYM) questionnaire score | Baseline and 10 weeks | Likert scale questionnaire with 20 items, each item scored 0-5, total score ranging from 0-100 with higher scores related to worse outcomes |
| Change in Modified Activity Questionnaire (MAQ) score | Baseline and 10 weeks | Questionnaire, units of total hours of exercise over past 12 months, no min or max scores, higher value related to better outcome |
| Change in Cystic Fibrosis Questionnaire Revised (CFQ-R) score | Baseline and 10 weeks | Likert scale questionnaire, 50 items, each scored 0-4, total score ranging from 0-100 with higher value reflecting better outcome |
| Change in erythrocyte sedimentation rate (ESR) | Baseline and 10 weeks | Laboratory test, measured in mm/hr |
| Change in c-reactive protein (CRP) | Baseline and 10 weeks | Laboratory test, measured in mg/L |
| Change in intestinal fatty acid binding protein (I-FABP) | Baseline and 10 weeks | Laboratory test, measured in ng/mL |
| Change in lean and fat mass | Baseline and 10 weeks | DXA body composition measures |
| Change in CGM average glucose | Baseline to 10 weeks | Continuous glucose monitoring |
| Change in CGM glucose management indicator (GMI) | Baseline to 10 weeks | Continuous glucose monitoring |
Countries
United States
Outcome results
None listed