Cystic fibrosis-related diabetes (CFRD) is the most common non-pulmonary manifestation of cystic fibrosis (CF), affecting up to 30% of adolescents and 50% of adults living with CF, according to the Cystic Fibrosis Foundation (CFF). CFRD is often asymptomatic and so the CFF recommends that people living with CF be screened for CFRD annually starting at 10 years of age using an oral glucose tolerance test.
Although early detection and treatment of CFRD can lead to significant clinical improvements and prolong life, rates of screening are poor, likely due to the burdensome nature of oral glucose tolerance testing (OGTT). Rates of OGTT screening in patients 10-17 years of age vary widely among CF care centers, ranging 5.9% to 100% with a median of 61.3% of patients at a given center completing screening. At Children’s National, only 46.4% of pediatric CF patients without CFRD completed the OGTT in 2019. The most commonly cited reason for failure to complete recommended OGTT screening is the additional burden that this time-consuming fasting test, requiring three blood draws, places upon patients who already contend with multiple medical interventions.
“People living with CF face tremendous medical burdens.,” says Brynn Marks, M.D., MSHPEd, pediatric endocrinologist at Children’s National Hospital. “Novel, more convenient approaches to CFRD screening that can provide both diagnostic and therapeutic information are urgently needed.”
Dr. Marks and Carol Chace, MSW, a social worker at Children’s National, have collaborated to receive a $160,000 Pilot and Feasibility Award from the CFF that will allow researchers to assess the feasibility and accuracy of two new CFRD screening tools, the Dexcom G6 Pro, a continuous glucose monitoring (CGM), and the Digostics GTT@home, a home-based OGTT kit. The Dexcom G6 Pro is the first unblinded professional CGM that enables patients to see their glucose values and trends in real-time. The GTT@home uses a built-in timer and audio-visual cues to guide users to collect capillary blood samples through finger sticks.
“While the idea of home-based testing is exciting in general, it is particularly important in the midst of the COVID-19 pandemic, as many are limiting preventative health care visits,” says Dr. Marks. “This research will hopefully inform future larger studies that could one day allow for this screening to be done at home.”