Managing Insulin Pumps for Exercise - Study 1
Condition: Type 1 Diabetes Mellitus
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 1
Study type: Observational

Summary: 
      People with Type 1 Diabetes Mellitus (T1DM) like to take part in sport and exercise, but
      problems with metabolism and blood glucose control can make this difficult. Some people with
      T1DM administer their insulin via an insulin pump, also know as continuous subcutaneous
      insulin infusion (CSII) therapy, in which a background or basal level of insulin is
      constantly infused under the skin by a special pump, with bolus doses of insulin given to
      accompany food. Clinical experience suggests that this may be particularly useful for
      managing diabetes for exercise, but there is limited experimental evidence to support this.
      The aim of this research , which is divided into three parts, is to investigate the
      hypothesis that the physiological response to sub-maximal (moderate) exercise of a person
      with type 1 diabetes treated with CSII, can be made to approximate more closely to the
      physiological response of a healthy individual by a prior reduction of their basal insulin
      infusion rate. This first part of the research is designed to compare metabolic response to
      exercise between people without diabetes and people with T1DM running there insulin pump at
      the usual basal rate.
    

Detailed description: 
      For the first part of the study, participants will be either people with type 1 diabetes
      treated with insulin pump therapy or volunteers without diabetes. The 2 groups will be
      matched as far as possible by age, body mass index and usual level of activity. Participants
      will attend an exercise laboratory on 2 occasions. On the first occasion, which can take
      place at any time of day, formal written consent will be obtained for participation in the
      study. Participants will then undergo measurement of maximal exercise capacity (VO2 MAX). On
      the second occasion they will attend 2 hours after a lunch containing 60 grams of
      carbohydrate (advice will be given on how this can be achieved). A cannula will be inserted
      on arrival and blood samples obtained. Arterialised samples will be obtained by using a
      heated hand technique. Once the cannula has been inserted participants with type 1 diabetes
      will be asked to reduce the basal insulin infusion rate on their insulin pump to 70% of
      normal until the end of the study visit. After 30 minutes a further set of blood samples will
      be obtained, and participants will then start to exercise for 1 hour at 50% VO2 MAX. A
      further set of blood samples will be obtained at the end of the hour of exercise.
      Participants will then rest for 30 minutes before a final set of blood samples is taken. At
      this point the cannula will be removed and the study visit ends. Participants with diabetes
      will be given the choice to return basal insulin infusion rate to normal at this point. A
      snack will be offered.

      Blood glucose will be monitored every 10 minutes and also if a participant feels symptoms of
      hypoglycaemia. If hypoglycaemia occurs the protocol will be stopped and carbohydrate given
      until the blood glucose level returns to the normal range.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Participants with Type 1 Diabetes treated with insulin pump therapy who exercise for at
        least 1 hour each week and comparable participants without diabetes mellitus
      
Biospecimen description: 
      All samples retained will be plasma samples. Any samples remaining after analysis will be
      retained until the 3 trials in this research study have been completed, and will then be
      destroyed.
    
Keywords: Type 1 Diabetes Mellitus; Exercise; Continuous Subcutaneous Insulin Infusion; CSII; Insulin Pump Therapy