Randomized Trial of the Insulin-Only iLet Bionic Pancreas for the Treatment of Cystic Fibrosis- Related Diabetes.

OBJECTIVE: Cystic fibrosis-related diabetes (CFRD) affects up to 50% of adults with cystic fibrosis and adds significant morbidity and treatment burden. We evaluated the safety and efficacy of automated insulin delivery with the iLet bionic pancreas (BP) in adults with CFRD in a single-center, open-label, random-order, crossover trial. RESEARCH DESIGN AND METHODS: Twenty participants with CFRD were assigned in random order to 14 days each on the BP or their usual care (UC). No restrictions were placed on diet or activity. The primary outcome was the percent time sensor-measured glucose was in target range 70-180 mg/dL (time in range [TIR]) on days 3-14 of each arm, and key secondary outcomes included mean continuous glucose monitoring (CGM) glucose and the percent time sensor-measured glucose was in hypoglycemic range <54 mg/dL. RESULTS: TIR was significantly higher in the BP arm than the UC arm (75 ± 11% vs. 62 ± 22%, P = 0.001). Mean CGM glucose was lower in the BP arm than in the UC arm (150 ± 19 vs. 171 ± 45 mg/dL, P = 0.007). There was no significant difference in percent time with sensor-measured glucose <54 mg/dL (0.27% vs. 0.36%, P = 1.0), although self-reported symptomatic hypoglycemia episodes were higher during the BP arm than the UC arm (0.7 vs. 0.4 median episodes per day, P = 0.01). No episodes of diabetic ketoacidosis or severe hypoglycemia occurred in either arm. CONCLUSIONS: Adults with CFRD had improved glucose control without an increase in CGM-measured hypoglycemia with the BP compared with their UC, suggesting that this may be an important therapeutic option for this patient population.

Real-world feasibility of short-term, unsupervised home spirometry in CF.

OBJECTIVES: The objective of this study was to study the performance of two available home spirometers used by people with Cystic Fibrosis (PwCF) over a short-term period and to assess user experience. STUDY DESIGN: This was a prospective observational study. Participants age 6 years and older were recruited to participate if they could complete acceptable spirometry in the clinic setting. METHODS: Participants used either the NuvoAir Air Next or the ZEPHYRx MIR Spirobank Smart spirometer. They underwent a one-time virtual training session, then completed 2 weeks of daily spirometry followed by 2 months of weekly spirometry. Participants responded to surveys and completed a debrief interview to understand user experience. Statistical analyses examined feasibility, reliability, and accuracy of each spirometer in an unsupervised, real-world setting. RESULTS: We report high adherence (80% [95% CI 61%-92%]) to our study protocol in all session attempts, but lower rates of adherence after discarding sessions performed with inadequate technique (47% [95% CI 28%-66%] to 63% [95% CI 44%-80%]). We found high reliability of each device by analyzing day-to-day variability and good concordance to recent in-clinic testing (NuvoAir r = 0.91 [0.82-0.93]; ZEPHYRx r = 0.70 [0.45-0.84]). Patient experience in this cohort was favorable with most reporting ease of use and reassurance knowing lung function was being tracked over time. CONCLUSIONS: This real-world study showed good performance of two different available home spirometers used by children and adults with CF. While overall adherence was high, suboptimal technique reduced the total interpretable data, possibly limiting feasibility. Future work should focus on developing sustainable training and coaching programs to support the success of home spirometry in a CF chronic care model.

Continuous Glucose Monitoring and HbA1c in Cystic Fibrosis: Clinical Correlations and Implications for CFRD Diagnosis.

CONTEXT: The clinical utility and implications of continuous glucose monitoring (CGM) in cystic fibrosis (CF) are unclear. OBJECTIVE: We examined the correlation between CGM measures and clinical outcomes in adults with CF, investigated the relationship between hemoglobin A1c (HbA1c) and CGM-derived average glucose (AG), and explored CGM measures that distinguish cystic fibrosis-related diabetes (CFRD) from normal and abnormal glucose tolerance. METHODS: This prospective observational study included 77 adults with CF who had CGM and HbA1c measured at 2 to 3 time points 3 months apart. RESULTS: Thirty-one of the 77 participants met American Diabetes Association-recommended diagnostic criteria for CFRD by oral glucose tolerance testing and/or HbA1c. In all participants, CGM measures of hyperglycemia and glycemic variability correlated with nutritional status and pulmonary function. HbA1c was correlated with AG (R2 = 0.71, P < 0.001), with no significant difference between this regression line and that previously established in type 1 and type 2 diabetes and healthy volunteers. Cutoffs of 17.5% time > 140 mg/dL and 3.4% time > 180 mg/dL had sensitivities of 87% and 90%, respectively, and specificities of 95%, for identifying CFRD. Area under the curve and percent of participants correctly classified with CFRD were higher for AG, SD, % time > 140, > 180, and > 250 mg/dL than for HbA1c. CONCLUSION: CGM measures of hyperglycemia and glycemic variability are superior to HbA1c in distinguishing those with and without CFRD. CGM-derived AG is strongly correlated with HbA1c in adults with CF, with a similar relationship to other diabetes populations. Future studies are needed to investigate CGM as a diagnostic and screening tool for CFRD.

The effect of elexacaftor/tezacaftor/ivacaftor (ETI) on glycemia in adults with cystic fibrosis.

BACKGROUND: Cystic fibrosis related diabetes (CFRD) is associated with pulmonary decline and compromised nutritional status. Emerging data suggest that CFTR dysfunction may play a direct role in the pathogenesis of CFRD; however, studies investigating the effect of CFTR modulators on glycemic outcomes in patients with cystic fibrosis (CF) have shown mixed results. The impact of elexacaftor-tezacaftor-ivacaftor (ETI) on glycemic control is currently unknown. Our objective was to investigate the effect of ETI initiation on glycemia in adults with CF using continuous glucose monitoring (CGM). METHODS: In this prospective observational study, 34 adults with CF and at least one F508del CFTR mutation wore CGM sensors for 14 days prior to starting ETI and again 3-12 months after ETI initiation. Hypoglycemia symptoms were queried at each visit, and most recent anthropometric measures and spirometry data were obtained by chart review. RESULTS: Twenty-three participants completed the study. Compared to baseline, average glucose (AG), standard deviation (SD), % time >200 mg/dL, and peak sensor glucose decreased with ETI treatment, and % time in target range 70-180 mg/dL increased. Improvements in glycemic parameters were most notable in individuals with CFRD. There was no significant change in CGM-measured or self-reported hypoglycemia before and after ETI initiation. CONCLUSION: Initiation of ETI in adults with CF was associated with improvement CGM-derived measures of hyperglycemia and glycemic variability with no effect on hypoglycemia. Further studies are needed to investigate underlying etiology of these changes and the long-term impact of ETI on glycemic control in patients with CF.