Hypoglycemia and Glucagon Response in CF
Condition: Cystic Fibrosis; Hypoglycemia; Glucagon Deficiency; Pancreatic Insufficiency
MeSH terms: Cystic Fibrosis; Exocrine Pancreatic Insufficiency; Hypoglycemia; Fibrosis
Study type: Observational

Summary: 
      The goal of this clinical trial is to investigate the etiopathogenesis of isolated
      hypoglycemia and hypoglycemia with abnormal glucose tolerance in children with Cystic
      Fibrosis (CF) and to evaluate the role of glucagon and pancreatic insufficiency on
      hypoglycemia in CF. The main questions it aims to answer are:

        1. Do isolated hypoglycemia and hypoglycemia with abnormal glucose tolerance have different
           etiopathogenesis?

        2. What is the role of pancreatic insufficiency in these two conditions? Participants were
           asked to perform 3-h OGTT and to take blood samples. Researchers compared with healthy
           peers to see if there is isolated hypoglycemia in OGTT and how is the glucagon response
           to OGTT in healthy peers.
    

Detailed description: 
      The exact underlying mechanism of hypoglycemia in CF is still unknown. Some recent studies
      support the delayed and prolonged insulin secretion and impaired counterregulatory hormone
      response as the reason of reactive hypoglycemia, whereas the others argued an additive effect
      of an intrinsic factor.

      However, the weakness of these limited studies is that nearly all of them included CF
      patients who had pancreatic insufficiency (PI) and could not reveal the mechanism of
      hypoglycemia seen in those without PI. In addition, there were no healthy controls for
      comparison of glucagon secretion in CF patients with hypoglycemia. Moreover, the studies that
      evaluate the role of glucagon in hypoglycemic CF patients were performed in hypoglycemic
      adult patients with abnormal glucose tolerance (AGT) and the delayed and prolonged insulin
      release is expected to be more likely as the reason of hypoglycemia in this setting.
      Previously, the investigators had demonstrated isolated hypoglycemia in some of the pediatric
      CF patients during OGTT. In this study, the investigators aimed to further investigate
      possible mechanisms of hypoglycemia. The investigators hypothesized that the mechanism of
      isolated hypoglycemia might be different from hypoglycemia seen in patients with AGT.
      Furthermore, the investigators evaluated the role of pancreatic insufficiency in hypoglycemia
      of CF patients by analyzing glucose, insulin and glucagon response to a glucose load in CF
      patients with and without PI.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study population is the children and adolescents aged 10-18 years with CF who were
        regularly followed-up at the Pediatric Endocrinology and Diabetes Units.

        The control group was age-matched healthy, diabetes non-diabetic siblings of patients with
        type 1 diabetes. All the controls were negative for β-cell autoantibodies (anti-glutamic
        acid decarboxylase, islet cell antibody, and insulin antibody).
      
Biospecimen description: 
      Blood samples