The SMART B Exercise Study :''The SMART Study''
Condition: Hypoglycemia
MeSH terms: Hypoglycemia
Study type: Interventional

Summary: 
      Despite the established health benefits conveyed by physical activity for people with type 1
      diabetes (T1D), participation rates remain low, with fear of hypoglycaemia, lack of freedom
      to engage in unplanned activities, and uncertainty in making appropriate adjustments to
      insulin and nutritional therapy reported as the leading barriers to regular exercise
      engagement. Indeed, the synergistic glucose lowering effects of peripheral hyperinsulinaemia
      and exercising muscle tissue accentuate the risk of exercise-related hypoglycaemia for
      individuals with T1D, particularly if performed post-prandially. Hence, the introduction of
      commercially available artificial pancreas systems, also known as ''advanced
      hybrid-closed-loop'' (AHCL) systems, that regulate insulin rates with minimal user
      interaction constitute compelling therapeutic aids with clinically relevant potential.
      Nevertheless, we know little about their safe and efficacious integration around dynamic
      physical exercise. Nor do we know how alterations in carbohydrate fueling strategies around
      exercise effect subsequent glucose trends.

      This study aims to 1) compare the efficacy of an AHCL system versus usual care insulin pump
      therapy, with carbohydrates taken before or during exercise, in optimising TIR around dynamic
      physical exercise and 2) explore the influence of carbohydrate intake before versus during
      exercise on the metabolomic, hormonal and physiological responses to exercise.
    

Detailed description: 
      Following successful completion of a screening visit, participants will attend the laboratory
      to complete 3 experimental visits during which they will undertake a 45-minute bout of
      moderate intensity continuous exercise on a bicycle ergometer at ~60% of the individualised
      VȮ2max. Prior to commencing exercise, participants will consume a standardised low-glycaemic
      index, carbohydrate-based meal (equating to 0.75g.CHO.kg.bm-1) with, or without, a 25%
      reduction in their meal-time insulin dose as well as with carbohydrates before or during
      exercise (according to the randomisation). Venous blood glucose sampling will be taken in
      15-minute intervals leading into and after exercise with 5-minute intervals performed during
      exercise. Samples will be used to retrospectively cross-compare the metabolic, hormonal, and
      physiological responses between visits. Visits 1 & 2 will be separated by ≥14 days to ensure
      adequate familiarisation with the AHCL system whilst visits 2 & 3 will be separated by
      ≥3days. Each participant will undertake 1 screening and 3 experimental visits equating to a
      total of 80 study visits.
    

Intervention name(s): Insulin pump
Intervention type(s): Device
Intervention description(s): Alterations in insulin pump therapy or carbohydrate consumption
Intervention MeSH terms: Insulin
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Three period randomised cross-over clinical trial
Masking: None (Open Label)
Primary purpose: Treatment