Background: Nutrition plays a pivotal role in long-term survival in cystic fibrosis (CF). Early insulin treatment for glucose intolerance promotes anabolism and stabilises lung function. However there is a variation in cystic fibrosis related diabetes (CFRD) screening across centres (recommended age for start of CFRD screening varies between 10 and 12 years as per CF trust, CFF & ISPAD guidelines).
Aims: To assess if early screening of glycaemic status helps in early identification of glucose intolerance in CF and the correlation between OGTT and glycosylated haemoglobin (HbA1c).
Methodology: Retrospective data on OGTT, HbA1c and patient demographics were collected on all CF patients in a tertiary paediatric hospital (n=84, 35M). Patients were categorised as <10, 10 to <12 & ≥12 years. The data was analysed to assess the incidence of glucose intolerance and to compare OGTT and HbA1c.
Results: Total of 127 OGTT were carried out in 35 CF patients with median age of 13 years (317.3) and median follow-up of 4 years(0.811.1). OGTT: Eleven patients (13%) were diagnosed with CFRD requiring various forms of insulin therapy including insulin pump. This includes three patients (27%) diagnosed with CFRD as a result of the early OGTT screening in 10 to <12 years. OGTT was undertaken in symptomatic children <10 years of age and identified one CFRD patient (aged 9.4 years). Five eligible patients (≥10 years of age) did not undergo OGTT (Table 1). HbA1c: Total of 89 HbA1c analyses was undertaken along with simultaneous OGTT (Table 2). The HbA1c was ≤42 mmol/mol in patients with IGT and >42 mmols/mol in patients with postprandial hyperglycaemia.
|Groups||Age in years median (range)||OGTT|
|<10 years||6.7 (39.8)||24||23||1 (PP-1)|
|10- <12 years||10.9 (1011.7)||16||12||4 (F-2, PP-2**)|
|≥12 years||13.8 (1217.3)||87||68||19 (F-2, PP-7, IGT-10)|
|Fasting hyperglycaemia (F)=blood glucose >7.0 mmol/l, Post prandial hyperglycaemia (PP)=blood glucose ≥11.1 mmol/l, Impaired Glucose tolerance (IGT)= post prandial blood glucose between 7.8 and 11.0 mmol/l. ** Same patient had two abnormal OGTT.|
|OGTT||HbA1c ≤ 42 mmol/mol||HbA1c > 42 mmol/mol||Total|
|Abnormal||12 (F-2, IGT-10)||8 (F-1, PP-7)||20|
Conclusions: i) Application of CFF guideline (CFRD screening ≥10 years of age) promotes early diagnosis and management of CFRD. ii) OGTT may not be routinely needed in children <10 years of age unless there are strong clinical indications. iii) A national consensus guideline on CFRD screening would be very useful.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology