Children and adolescents with cystic fibrosis attending the three specialist Dublin respiratory units : clinical, metabolic, quality of life and genetic aspects

Abstract

Patients with cystic fibrosis related diabetes (CFRD) have a six-fold increase in morbidity and mortality (Moran, 2002a). CFRD is usually asymptomatic and can remain undetected for up to four years prior to diagnosis. Intensive CGM monitoring in the normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) stages may be the key to earlier diagnosis in CFRD. Early treatment of children and adolescents with cystic fibrosis (CF) has been proven to improve their growth, lung function and reduce the number of chest infections yearly (Lanng et al., 1994b). Over a 12 month period, a cohort of 102 children with CF were assessed prospectively in the three Dublin Specialist Respiratory centres to ascertain: the prevalence of glucose intolerance, the use and validity of continuous glucose monitoring (CGM), insulin and c-peptide levels, genetic gene associations, quality of life (QOL) and dietary intake. This study has established the prevalence of 70% NGT, 14% IGT and 16% CFRD in a cohort of 102 children with CF attending the three Dublin Tertiary Paediatric Hospitals. The total prevalence for abnormal glucose tolerance in this study is high at 30%. Initial classification at baseline (Time=0) was based on standard oral glucose tolerance testing (OGTT). At baseline 8 children were diagnosed with CFRD and by study completion 26 children were treated with insulin. Clinical demographics revealed males were lighter and their body mass indexes (BMI) were lower than the national averages for age. These weight and BMI differences were not seen in females. All children had reduced pulmonary function measured by forced expiratory volume in one second (%FEVi) with a mean of 68%. Our study reports the %FEVi as 69%, 48% and 31% had mild, moderate and severe lung disease respectively. There were no significant differences between the three glucose tolerance groups for clinical parameters such as weight, height and BMI; however, children with CFRD had significantly lower lung function, p<0.04.