Abstract
BACKGROUND: Cystic fibrosis related diabetes (CFRD) with fasting hyperglycemia is found in 15% of adult and 11% of adolescent CF patients. Because of concerns about hypoglycemia, it is not common practice to treat CFRD with 24-hour basal insulin therapy, despite evidence that insulin deficiency may contribute to protein catabolism and have an adverse effect on weight, muscle mass, pulmonary function, and, ultimately, survival. We hypothesized that insulin glargine would improve blood glucose control and weight in patients with CFRD without causing hypoglycemia. METHODS: A randomized cross-over study compared 12 weeks each of bedtime NPH or glargine in 19 CFRD patients. RESULTS: There was significantly greater reduction in fasting plasma glucose with glargine (P=0.03), and participants showed a non-significant trend towards weight gain with this insulin (P=0.07). No serious hypoglycemia occurred. At study end, all patients chose to continue glargine. CONCLUSIONS: A study of longer duration is needed to determine whether insulin glargine impacts protein catabolism and overall clinical status in CF patients, but these initial data suggest that this is a promising therapy in CFRD.