Continuous glucose monitoring in cystic fibrosis: glycemic relationships, 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...