Introduction
Background
Patients with type 1 diabetes mellitus (T1DM) who exercise regularly have to take less insulin, have a better lipid profile and are more likely to reach their HbA1c and blood pressure targets than inactive patients.1 2 They are also more likely to have a better quality of life.1
Based on these findings, guidelines recommend that all adults with T1DM accumulate 150 min/week of moderate to vigorous aerobic exercise with no more than 2 consecutive days of doing no activity.3
How active are patients with T1DM?
Many people with T1DM struggle to meet the recommended levels of exercise. Sixty-three percent of German and Austrian people with T1DM, in a cross-sectional study, reported doing no regular physical activity (PA).4 Similar results were found in a Finnish study, where 43% of people with T1DM were doing less than one session of PA per week.5 Studies in which PA has been measured objectively have found similar findings. In a Canadian study only 43% of women and 55% of men with T1DM were active.6 In a UK study, newly diagnosed adults with T1DM spent a quarter less time in moderate to vigorous PA per day than healthy matched controls.7
What are the barriers to exercise in people with T1DM?
Normally when exercising, changes in insulin and counter-regulatory hormone secretion are made which are dependent on the type of exercise being performed. These changes facilitate an increase in liver glucose production, which matches skeletal muscle glucose uptake during exercise.8 A change in the secretion of these hormones is also seen after activity to facilitate recovery and adaptation to the exercise. As a result of these changes, blood glucose levels remain stable before, during and after exercise.
In T1DM, fuel regulation is difficult as the insulin level does not fall in response to exercise and there may be impaired secretion or action of counter-regulatory hormones, making normal fuel regulation difficult. After activity the inability of the pancreas to increase insulin if needed, and reduced blood concentrations of counter-regulatory hormones can hamper recovery and adaptation to exercise. This means that hypoglycemia both during and following exercise becomes a significant risk. Furthermore, hyperglycemia prior to, and following, some types of exercises can also be problematic.9 In order to prevent these problems patients with T1DM need to make changes to their insulin dosages and nutrition to try and mimic the normal physiological responses seen with the exercise they are undertaking. This requires a lot of skill and extensive knowledge.
In people with T1DM many of the barriers, motivators and facilitators to PA are similar to the general public, such as lack of time, work pressures and bad weather.10 In addition, they worry about having low blood glucose during exercise and how they should adjust their insulin and carbohydrate intake to keep glucose stable around exercise. Improved knowledge on how insulin works and education on how to minimize high and low blood glucose excursions with exercise helps reduce these anxieties. Reluctance of physicians to recommend exercise to people with T1DM can also be a barrier.11
Where do patients with T1DM obtain information about diabetes management when exercising?
No national validated education program for people with T1DM around exercise exists, which means that patients must obtain information on this subject from their healthcare workers, internet sites, books, and pamphlets. Information from these sources tends to be generic and not detailed enough to take into account the precautions required for differing type, duration and intensity of exercise. Similarly, no validated courses exist for healthcare professionals (HCP) to learn how to manage and support patients on nutritional adjustments for diabetes and activity. Thus they are left to obtain information from conference lectures, journals, books and websites. Again this advice tends to be generic and insufficiently detailed. Not surprisingly, many HCPs who work regularly with patients with T1DM feel they lack the knowledge and confidence to advise patients on strategies to manage their diabetes when undertaking exercise.
In light of this, we undertook an internet survey to try and understand the knowledge levels of HCPs who were giving advice about activity to people with T1DM. In this survey of 252 HCPs, knowledge levels were poor. For example, two-thirds did not know what advice to give patients on what to do with their short-acting or long-acting insulin when active and two-thirds were unable to identify the time point at which patients were most likely to experience hypoglycemia with different sports. A total of 91% of HCPs felt they would like formal training in exercise prescription for people with T1DM.12
Overarching aim
The overarching aim of this study is to support safe exercise for people with T1DM. The specific aim is to develop and pilot an education program for such people (with accompanying training for HCPs to deliver this program) to guide insulin and carbohydrate adjustment for safe exercise. The results will be used to design a definitive trial to assess the effect of this education program on exercise levels in people with T1DM.
Study design and specific outcomes
This is a multicenter study, divided into two phases (see study flow sheet, figure 1).
In phase 1, the primary aim is to develop an education program for patients with T1DM and accompanying training for HCPs who regularly work with patients with T1DM to guide insulin and carbohydrate adjustment for safe exercise.
In phase 2, the primary aim is to conduct a pilot randomized controlled trial (RCT) to:
Determine the number of people with T1DM who would be eligible to participate in an RCT of such an education program.
Determine the proportion of these people who would be willing to participate in this trial (ie, recruitment rate), and their characteristics.
Define the rates of adherence to the intervention and participant dropout from the study, particularly to determine whether retention differs between the usual care and intervention arms.
Generate estimates of statistical properties of potential outcome measures (eg, variances) that are needed for sample size calculations for the definitive trial. The outcome measures that will be assessed are exercise, fear of hypoglycemia, frequency of hypoglycemia, self-reported barriers to exercise, and well-being.
We will also pilot methods for collecting outcome measures and assess the acceptability of these outcome measures. We will also validate our processes for recruitment, randomization, treatment, and follow-up assessments. Information from phase 2 will enable us to design with confidence a definitive RCT to assess the effect of this education program in patients with T1DM.