Clinical Focus
31 OCTOBER 2025 ausdoc. com. au
| THE | DIABETES & WEIGHT MANAGEMENT SPECIAL
Case Report
Helping to close the loop
on glycaemic control
A patient’ s experience of evolving technology for type 1 diabetes management highlights the gains such devices can help achieve in control and quality of life.
Time in Ranges
Goals for type 1 and Type 2 Diabetes
Each 5 % increase in the Target Range is clinically beneficial Each 1 % time in range = about 15 minutes per day
36 % Very High
Goal: < 5 %
28 % High
35 % In Range
Goal: > 70 %
64 %
Goal: < 25 %
1 % Low
< 1 % Very Low
Goal: < 1 %
1 %
Goal: < 4 %
Target Range: 3.9-10.0 mmol / L Very High: Above 13.9 mmol / L Very Low: Below 3.0 mmol / L
Amy Rush Accredited practising dietitian and credentialled diabetes educator, type 1 diabetes specialist clinical practitioner, Type 1 Diabetes Family Centre, Perth, WA.
KAYE is a 60-year-old woman with a highly demanding job as a CEO. She was diagnosed with type 1 diabetes at age 54 and started on basal insulin glargine and bolus insulin aspart. Kaye uses a bolus calculator to determine meal doses and is diligent about administering insulin at breakfast and lunch. She is less likely to bolus for the evening meal, attributing this to exhaustion and fear of overnight hypoglycaemia.
Kaye’ s care plan includes regular checkups with a GP, endocrinologist, diabetes educator and dietitian, working on education and changes in insulin dosing. Continuous glucose monitoring( CGM) was implemented 12 months previously.
Despite her efforts, Kaye has only seen small improvements in her CGM-tracked time in range( TIR) with a target BSL of 3.9-10mmol / L. She experiences erratic BSLs during the day and consistent hyperglycaemia overnight. Kaye reports poor sleep quality, waking with headaches and feeling exhausted.
She recalls being told early in her diagnosis that she has‘ brittle diabetes’ and has accepted that blood glucose instability is part and parcel of the condition. Additionally, Kaye feels her efforts are futile which fuels reversion to old habits of missed meal boluses and forgotten basal doses.
At her latest checkup Kaye’ s HbA1c is 8.4 %( target < 7 %) and her TIR is 25 %( target ≥70 %).
Management
After discussions with her care team, Kaye decides to trial a hybrid closed loop( HCL) system. She chooses a delivery device which offers sleep activity, allowing for closer monitoring and dose adjustment overnight. She hopes this might improve her long-term overnight hyperglycaemia and sleep, while also providing peace of mind about prevention of hypoglycaemia.
In the two weeks prior to implementing the HCL device, Kaye’ s estimated HbA1c is 8.5 % and her TIR is 35 %( see figure 1).
She has significant post-meal hyperglycaemia at dinner followed by an overnight average sensor glucose level( SGL) above 10mmol / L, despite late
Glucose Metrics
Average Glucose
Goal: < 8.5 % mmol / L
evening insulin aspart corrections( see figure 2).
The flow-on effect is hyperglycaemia throughout the day, despite counting carbohydrates and bolusing for breakfast and lunch meals.
Discussion
Insulin pumps have been a breakthrough in management of type 1 diabetes in recent years. They infuse basal insulin over 24 hours and deliver bolus insulin on demand. Recent advancements
12.0 mmol / L
GMI
8.5 %
Goal: < 7 %
Coefficient of Variation
39.4 %
Goal: < 36 %
Time CGM Active
97.4 %
have seen the inclusion of CGM to pumps to create HCL systems. HCL algorithms use predicted SGL from CGM to titrate insulin to achieve target glucose and deliver bolus insulin on demand. 1 Transition to HCL technology improves HbA1c and TIR for patients with type 1 diabetes. 1, 2, 7
Different HCL devices offer varying functions around monitoring and adjustment settings and algorithms, which may include modes that can be programmed to adjust for sport
Figure 1: Kaye’ s continuous glucose monitoring( CGM) averages for the two-week period prior to starting hybrid closed loop insulin pump use. GMI = glucose management indicator.
Figure 2: Kaye’ s continuous glucose monitoring averages for the two-week period prior to starting hybrid closed loop insulin pump use.
and activity, and sleep. In this case the patient opted for a system which includes the option to monitor and adjust based on sleep parameters. This system titrates insulin delivery based on CGM sensor glucose, with the goal of maintaining SGL between 6.2-8.9mmol / L during waking hours and increasing TIR. 3
Improved TIR overnight is to be expected generally with type 1 diabetes, given the absence of food, activity and other daytime factors impacting