Insulin improves clinical status of patients with cystic-fibrosis-related diabetes mellitus

Cystic-fibrosis-related diabetes mellitus is frequently underdiagnosed and associated with deterioration of overall clinical status. The purpose of th is prospective study was to investigate the influence of insulin on nutriti on, lung function and clinical status of cystic fibrosis patients. For a pe riod of 5 y, and at 6-mo intervals, body mass index, forced expiratory volu me in 1 sec, Shwachman score, intravenous glucose tolerance test and first- phase insulin response were determined in 30 cystic fibrosis patients (age range 10-35 y) with exocrine pancreatic insufficiency. During the study per iod, six patients (3M and 3F; age range 15-22 y) developed diabetes and req uired insulin therapy. The decrease of first-phase insulin response coincid ed with deterioration of nutritional and clinical status, which improved si gnificantly 6 mo after the institution of insulin. Conclusion: Insulin, as an anabolic hormone, could have an influence on bod y mass, which may affect pulmonary function and clinical condition in cysti c fibrosis. It is important to identify cystic fibrosis individuals at risk of developing diabetes so that early insulin therapy is instituted.