Study design (if review, criteria of inclusion for studies)
Randomized double-blind trial
Twenty-six adults from Children's Hospital of Philadelphia and University of Pennsylvania CF Center with PI-CF and AGT (defined by oral glucose tolerance test glucose [mg/dL]: early glucose intolerance [1-hour â¥155 & 2-hour <140], impaired glucose tolerance [2-hour â¥140 and <200 mg/dl], or diabetes [2-hour â¥200]). 24 completed the trial (n=12 sitagliptin; n=12 placebo).
Patients were randomized to a 6-month double-blind trial of DPP-4 inhibitor sitagliptin 100 mg daily or matched-placebo
Main outcome measures were mixed-meal tolerance test (MMTT) responses for intact GLP-1 and GIP, insulin secretory rates (ISR), glucagon suppression, and glycemia and glucose-potentiated arginine (GPA) test-derived measures of Î²- and Î±-cell function.
Following 6-months of sitagliptin vs. placebo, MMTT intact GLP-1 and GIP responses increased (P <0.001), ISR dynamics improved (P <0.05), and glucagon suppression was modestly enhanced (P <0.05) while GPA test responses for glucagon were lower. No improvements in glucose tolerance or Î²-cell sensitivity to glucose, including for second-phase insulin response were found.
In glucose intolerant PI-CF, sitagliptin intervention augmented meal-related incretin responses with improved early insulin secretion and glucagon suppression without affecting post-prandial glycemia.