Oral Presentation Australian Diabetes Society and the Australian Diabetes Educators Association Annual Scientific Meeting 2016

Overnight Glucose and Counter-regulatory Hormone Profiles in Type 1 Diabetes Adults during Closed Loop Insulin Delivery vs Sensor Augmented Pump with Low Glucose Suspend (#160)

Anneke Graf 1 , Glenn M. Ward 1 2 , Sara Vogrin 2 , Amin Sharifi 1 , Dilshani Jayawardene 1 , Jodie C. Horsburgh 1 , Margaret M. Loh 1 , Vijaya Sundararajan 2 , Alicia J. Jenkins 1 2 3 , Peter G. Colman 4 , Leon Bach 5 , Kavita Kumareswaran 5 , Richard J. MacIsaac 1 2 , Timothy W. Jones 6 , David N. O'Neal 1 2
  1. Department of Endocrinology and Diabetes, St Vincent's Hospital, Melbourne, VIC, Australia
  2. University of Melbourne Department of Medicine, St Vincent’s Hospital , Melbourne, VIC, Australia
  3. NHMRC Clinical Trials Centre, University of Sydney, Camperdown, NSW, Australia
  4. Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Melbourne, VIC, Australia
  5. Department of Endocrinology and Diabetes, Alfred Hospital , Melbourne, VIC, Australia
  6. Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, Perth, WA, Australia


We aimed to investigate glucose and counter-regulatory hormone profiles in adults with type 1 diabetes using an overnight closed-loop glucose sensing insulin delivery system (CL) compared to sensor-augmented insulin pump therapy with low glucose suspend (SAP+LGS).


Twelve adults with type 1 diabetes (mean HbA1c 7.3%) participated in an unmasked, randomised-crossover study over two non-sequential nights in a clinical trial centre (CTC) utilising either a CL (proportional integral derivative with insulin feedback algorithm, Medtronic ) or SAP+LGS technology (Enlite ImproveTM Sensor Augmented VeoTM System, Medtronic). Hourly samples for glucose, insulin, and counter-regulatory hormones (glucagon, growth hormone, cortisol, catecholamines) were collected. Plasma metanephrines were measured at the beginning and conclusion of the study night and 12-hour urinary collections were performed during the study night and the following 12 hours for measurement of cortisol and catecholamines.


All results are median (interquartile range). CL and SAP+LGS % time spent in target range (4-8mmol/L) between 22:00hrs to 08:00hrs was 91 (87, 98)% vs 96 (65,100)%; p=0.31; % time spent <4mmol/L was 0 (0, 8)% vs 0 (0, 6)%; p=0.89; and glucose standard deviation was 1.5 (1.2,1.8) mmol/L vs 1.3 (0.7, 2.5) mmol/L; p=0.54 respectively. Counter-regulatory hormone levels during CL and SAP+LGS did not differ and did not correlate with glycaemic parameters either overnight or during the next day.


Both CL and SAP+LGS performed well during an overnight CTC stay in this group of adults with well-controlled type 1 diabetes. Hypoglycaemia and overnight excursions of counter-regulatory hormones that impacted on glucose levels during the following day were avoided by both insulin delivery approaches. Whether the findings of this study can be replicated in a real life setting (ie. at home), in studies of greater duration and in groups with poor glycaemic control remains to be determined.