To describe the history, mechanisms, and consequences of cystic fibrosis (CF)–related diabetes, from childhood to early adulthood.

Pancreatic β-cell function was estimated from the plasma insulin/glucose ratios during oral glucose tolerance test (total area under the curve and ΔI_30-0min/G_30min, homeostasis model assessment [HOMA]%B), insulin sensitivity with the HOMA%S index, in 237 children with CF (109 boys, 128 girls). Progression of glucose metabolism abnormalities was evaluated by analysis for interval censored data; rates of pulmonary transplantation and death by Kaplan-Meier analysis.

Impaired glucose tolerance was found in 20% of patients at 10 years, 50% at 15 years, 75% at 20 years, 82% at 30 years; for diabetes, >20% at 15 year, 45% at 20 years, 70% at 30 years; for insulin treatment, 30% at 20 years, 40% at 30 years. Early impairment was associated with lower survival rates and higher rates of lung transplantation. The area under the curve_glucose correlated with decreased body mass index and height. Decrease in early insulin secretion (ΔI_30-0min/G_30min) was associated with impaired glucose tolerance, in all estimates of insulin secretion with diabetes. HOMA%S did not differ between the groups. Increased inflammation correlated with insulin resistance and impaired glucose tolerance.

CF-related diabetes, mainly because of β-cell deficiency, is frequent early in life and associated with impaired nutritional state and growth, increased rates of terminal respiratory failure, and death.