Continuous Glucose Monitoring in Routine Clinical Practice is Not Useful in Predicting Progression to Cystic Fibrosis Related Diabetes in a Small Sized Adult Service — ASN Events
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  3. Continuous Glucose Monitoring in Routine Clinical Practice is Not Useful in Predicting Progression to Cystic Fibrosis Related Diabetes in a Small Sized Adult Service

Continuous Glucose Monitoring in Routine Clinical Practice is Not Useful in Predicting Progression to Cystic Fibrosis Related Diabetes in a Small Sized Adult Service (#292)

Roland W McCallum 1 2 , Venkat Parameswaran 2 , David Reid 3
  1. School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
  2. Royal Hobart Hospital, Hobart, TAS, Australia
  3. Menzies Research Institute, Hobart, Tasmania, Australia

It has become clear in recent years that detection of the development of Cystic Fibrosis Related Diabetes as early as possible can help prevent deterioration in clinical status. Patients started on insulin can avoid weight loss and reduction in lung function (1).

 We investigated the use of Continuous Glucose Monitoring (CGM) in all willing patients with normal glucose (NGT) or impaired glucose tolerance (IGT) by Oral Glucose Tolerance Testing (OGTT) known to the Tasmanian Adult CF Unit (TACFU). The endpoint of the study was the development of CFRD as defined by OGTT, HbA1c > 6.5% or random glucose measurement ≥ 11.1 mmol/l. Patients were tested initially in 2007/2008 and followed up over 5 years. The study was approved by the Tasmanian Health and Research Ethics Committee.

Eleven patients underwent OGTT and CGM out of 44 patients known to TACFU. These patients did not show a reduction in FEV1 or weight over the year prior to testing. One patient left the State and one on CGM testing was immediately found to have developed diabetes. Thus nine patients were followed of whom five developed CFRD in the next 5 years.

We were unable to identify any statistical method which predicted the development of CFRD more accurately using CGM than simply using the OGTT. In particular looking for a CGM trace which had a least one glucose measurement ≥ 11.1 mmol/l, significantly greater glycaemic variability (measured by Standard Deviation) or significantly greater Area Under the Curve (AUC) were not superior.

This finding is in contrast to some other studies which did find CGM useful. However, these were carried out in centres with large groups of patients making trends easier to identify and in patient groups which when analysed showed clinical deterioration prior to using CGM (2,3).

Thus we believe that in small sized units with modest numbers of CF patients there is little additional benefit in carrying out the costly and time-consuming procedure of CGM in CF patients with clinically stable disease.

  1. Lanng, S., Thorsteinsson, B., Nerup, J., and Koch, C. Influence of the development of diabetes mellitus on clinical status in patients with cystic fibrosis. Eur. J. Pediatr. 1992; 151: 684–687
  2. Franzese A, Valerio G, Buono P, Spagnuolo MI, Sepe A, Mozzillo E, De Simone I & Raia V. Continuous glucose monitoring system in the screening of early glucose derangements in children and adolescents with cystic fibrosis. Journal of Pediatric Endocrinology & Metabolism 2008 21 109–116.
  3. Schiaffini R, Brufani C, Russo B, Fintini D, Migliaccio A, Pecorelli L, Bizzarri C, Lucidi V, Cappa M. Abnormal glucose tolerance in children with cystic fibrosis: the predictive role of continuous glucose monitoring system. Eur J Endocrinol. 2010 Apr;162(4):705-10