The Effects of the CF Carrier State on the Kidneys and Pancreas

The overarching hypothesis is that CF carriers are at increased risk for developing most of the extrapulmonary conditions associated with CF compared to the general population. Specifically, it is hypothesized that this pilot data will detect subclinical evidence of pancreatic and kidney disorders among CF carriers. This will be determined by bringing CF carriers and controls to the CRU for one visit where they will answer survey questions and undergo laboratory testing. Additionally, they will collect urine and stool samples at home that will be sent to outside laboratories for testing.

Study Overview

• Status: Recruiting
• Conditions: Kidney Diseases; Pancreatic Disease; Carrier State

Detailed Description

There are 2 main study components- a clinic visit (all participants) and at-home specimen collections (volunteer subsample only). Each procedure is described below.

Clinic Visit Procedures (all participants):

Height- Height will be measured to the nearest 0.5 cm. Shoes should be removed.

Weight- Weight will be measured to the nearest 0.5 kg. Shoes and any extra jackets/sweaters/layers should be removed.

Blood Pressure- Blood pressure will be measured using the following procedures- Make sure that the participant hasn't smoked for 20 minutes prior to the BP measurement. Remove all clothing that covers the location of the cuff placement. Have the participant sit comfortably in a chair, with back supported, legs uncrossed and feet flat on the floor, arm supported at the level of the heart on a table, palm facing upward. Be sure to choose a cuff that correctly fits the participant's arm size. The lower end of the cuff should be ½ to 1 inch above the inner side of the elbow joint. The middle of the cuff should be at the level of the right atrium. Place the cuff snugly around the bare upper arm so that you can only insert one finger between the cuff and the arm.

Blood Draws/2-Hour OGTT- The participant should be active and eat a regular diet for three days prior to the test. They should be instructed not to eat or drink anything except water for at least 8 hours before the test. Someone trained in phlebotomy will insert an IV into the patient's arm so that blood draws can occur before and after the oral glucose tolerance test (OGTT). They will draw 2 tubes of blood (one 3 ml lavender top tube for HbA1C and one 4.5 ml green plasma separator tube for glucose, insulin, c-peptide, and lipid values). Then, a team member will provide the participant with a chilled Fisherbrand Glucose Tolerance Test Beverage (10 oz beverage, 75 g concentration) to drink. The participant must drink the entire beverage within 5 minutes. The patient should remain seated during the 2-hours of the test. They should not eat or drink anything except for plain water during the test (no mints, cough drops, chewing gum, or smoking).

At the 1-hour mark, 1 tube of blood (4.5 ml green plasma separator tube for glucose and insulin values) will be drawn.

Once the 2 hours have passed, 2 more tubes of blood (one 3 ml lavender top tube for c-reactive protein, calprotectin, and lactoferrin and one 4.5 ml green plasma separator tube for glucose and insulin values) will be drawn.

During the downtime between blood draws, the participant will answer the questions from the baseline survey and report their current medications interview-style with the research team member.

This visit is expected to last 3-4 hours.

Home Specimen Collection (volunteer subsample only; volunteers may do urine and/or stool samples):

Participants will be given specimen collection containers and instructions on collecting the 24-hour urine sample and/or stool sample, whichever they volunteer to collect. Finally, a date, time, and meeting location will be scheduled to return the samples to the research team.

• Study Type: Observational
• Enrollment (Estimated): 1250

Contacts and Locations

• Study Contact: Name: Philip M Polgreen, MD; Phone Number: (319) 384-6194; Email: philip-polgreen@uiowa.edu
• Study Contact Backup: Name: Shelby L Francis, PhD; Phone Number: 319-678-8037; Email: shelby-francis@uiowa.edu

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Recruiting
      • University of Iowa Hospitals and Clinics
      • Contact: Shelby L Francis, PhD; Phone Number: 319-678-8037; Email: shelby-francis@uiowa.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 100 years (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

CF Carriers and Controls who are not CF carriers.

Description

CF Carrier Inclusion Criteria:

• A CF Carrier identified via genetic testing

Control Inclusion Criteria:

• No previous CF carrier test results

Exclusion Criteria:

• CF patient status
• Unable to speak English
• Currently pregnant
• Unable to provide written informed consent
• Prisoner status
• Currently taking any medications for the treatment of diabetes

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Cystic Fibrosis Carrier Group; Participants who have been identified as Cystic Fibrosis Carriers via previous genetic testing.
Control Group; Participants who have been identified as not being Cystic Fibrosis Carriers via previous genetic testing.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of Glucose Values	Comparison of glucose values in cystic fibrosis carrier group vs control group via t-tests.	At baseline
Comparison of Insulin Values	Comparison of insulin values in cystic fibrosis carrier group vs control group via t-tests.	At baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of C-Reactive Protein Values	Comparison of c-reactive protein values in cystic fibrosis carrier group vs control group via t-tests.	At baseline
Comparison of Lactoferrin Values	Comparison of lactoferrin values in cystic fibrosis carrier group vs control group via t-tests.	At baseline
Comparison of Calprotectin Values	Comparison of calprotectin values in cystic fibrosis carrier group vs control group via t-tests.	At baseline
Comparison of Lipid Values	Comparison of lipid values in cystic fibrosis carrier group vs control group via t-tests.	At baseline

Collaborators and Investigators

• Sponsor: Philip Polgreen
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); National Institutes of Health (NIH)
• Investigators: Principal Investigator: Philip M Polgreen, MD, University of Iowa

Study record dates

Study Major Dates

• Study Start (Actual): December 20, 2021
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): July 1, 2026

Study Registration Dates

• First Submitted: July 22, 2022
• First Submitted That Met QC Criteria: July 22, 2022
• First Posted (Actual): July 26, 2022

Study Record Updates

• Last Update Posted (Estimated): January 7, 2026
• Last Update Submitted That Met QC Criteria: January 5, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Digestive System Diseases; Kidney Diseases; Pancreatic Diseases
• Other Study ID Numbers: 202012447; 5P30DK054759 (U.S. NIH Grant/Contract)

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