Slow-release insulin in cystic fibrosis patients with glucose intolerance: a randomized clinical trial

Background: Early stages of glucose metabolism impairment are a period at risk in the long-term prognosis of cystic fibrosis (CF). Slow-release synthetic insulin glargine can be a therapeutic tool in this metabolic condition. Methods: In this phase 3 multicenter, controlled, two-arm, randomized clinical study, glargine was administered up to a dosage of 0.15 U/ kg/ die for a period of 18 months. Primary endpoint was the improvement of nutritional status [ body mass index (BMI) Z score], while glucose tolerance [ hemoglobin A1c (HbA1C) and respiratory function (FEV1 predicted] improvement were the secondary endpoints. Results: Thirty-four subjects (18 in the glargine arm and 16 in the control arm) were evaluated. Adherence to insulin treatment was excellent. No significant adverse events were reported. There were no significant differences in BMI, HbA1C and FEV1 values between the two groups nor within groups, except for HbA1C improvement in the glargine arm at month + 18 (p = 0.04). Conclusions: Glargine treatment was well accepted and tolerated. No real efficacy in improving clinical and glycometabolic conditions was demonstrated. Further studies are necessary to test glargine at higher dosage and for a longer follow-up period.