Improvement of Care & Outcome


Sarah Koning

Dietary interventions in closed loop systems - Changing clinical nutrition approaches. Oral presentation at ISPAD 2023

Advanced closed-loop (aHCL) systems are currently improving T1D care dramatically. Not much is known yet about the effects of eating patterns of people with diabetes (PWDs) on the use of aHCL systems. Although the algorithms in these systems take care of basal insulin administration and provide autocorrection boluses, meal announcements (i.e. some level of carbohydrate counting) are still necessary. It is likely that specific dietary behaviours like alcohol (ab)use will affect the performance of aHCL systems. Vice versa, use of these systems may affect certain food choices which, combined with different total daily insulin doses, may affect weight control.


These systems have been in use for about two years now and numerous studies have been published and many are ongoing. At ISPAD 2023 Sarah Koning, dietician at Diabeter, presented results of a literature search, combined with case studies of PWDs treated at Diabeter, focusing on the questions:


  • Can carbohydrate (carb) counting be eliminated altogether when using aHCL systems?
  • How does alcohol (ab)use interfere with the use of aHCL systems?
  • What is the impact of an aHCL system on food choices and weight control?

Key findings:

Carb counting

  • Carb counting is burdensome, especially for pediatric populations due to irregular food intake. HbA1c of PWDs who are not able or willing to count carbohydrates improves dramatically with the use of aHCL systems
  • Despite decreasing Time In targeted glucose Range (TIR), not announcing meals up to 80 g of carbs does not result in serious adverse events (severe hypoglycemia or DKA)
  • Announcing meals to aHCL systems with precise carb counting (with 1g increments) results in better TIR compared with announcing fixed-group meals (regular, 40-70 g; large, 60-90 g; snack 15-20 g), but:
    • Announcing fixed-group meals still results in attaining TIR according to guidelines, thanks to autocorrection boluses
    • HbA1c does not seem to be affected by announcing fixed-group meals
  • Since meals do not only consist of carbs, carb counting skills are still very important when aHCL systems are used
  • Precise carb counting may not be needed with aHCL systems, however education on healthy eating patterns is still paramount (including education on healthy nutrition, premeal blousing and meal size and composition)
  • PWDs who do not practice precise carb counting should be made aware of the consequences of a ‘’more aggressive algorithm’’ that administer a high number of autocorrection boluses

Managing alcohol intake:

  • Alcoholic drinks:
    • Can result in delayed hypoglycemia by interfering with the liver’s efforts to release glucose
    • Can result in hyperglycemia due to high sugar content of many alcoholic drinks or due to increased snacking while drinking alcohol
  • Young people with T1D have a high risk of alcohol-related hospital admissions, particularly from 14 to 17 years old\
  • It is important to adjust system settings when consuming alcohol (e.g. temporary targets or initiating activity mode)

Weight control

  • PWDs using aHCL feel less burdened, increase portion sizes and eat more fatty foods
  • No signs yet of weight (BMI z-scores) increase after 12 months of aHCL use among PWDs 5-16 years of age


Please click here for the presentation.

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