Hypoglycaemia in cystic fibrosis: An analysis of a single centre adult cystic fibrosis clinic.

Background: Hypoglycaemia in cystic fibrosis (CF) is known to occur during oral glucose tolerance tests (OGTT) and continuous glucose monitoring, however demographic, clinical and mechanistic data are limited. The aims of this study were to review patient electronic medical records (EMR) in order to 1) describe patient characteristics of a university teaching hospital CF clinic, 2) determine the prevalence of hypoglycaemia on OGTT and explore associations with demographic and clinical characteristics, and 3) explore patient reported symptoms suggestive of hypoglycaemia documented in the EMR.

Methods: Adults who attended the RPA CF clinic between January 2009 to April 2016 were included in the study. The prevalence of hypoglycaemia on OGTT was determined and clinical and demographic data were compared to age, sex and glucose tolerance matched controls. Reported symptoms suggestive of hypoglycaemia documented in EMR were qualitatively explored.

Results: Hypoglycaemia on OGTT was prevalent in 25 (3 fasting and 22 reactive) of 169 patients who had an OGTT. They were heavier, less likely to have pancreatic insufficiency and had a lower insulin response at 2-h. Another 14 patients reported symptoms suggestive of hypoglycaemia in their EMR. No patient appropriately suppressed insulin at 2-h on OGTT.

Conclusions: This study identified two potentially different presentations of hypoglycaemia occur in different clinic sub-populations. Knowledge gaps in the aetiology and triggers of hypoglycaemia remain.