Exploring Exercise In Type 1 Diabetes: Intervention With An On-Line Educational Tool

In day to day life, people living with type 1 diabetes, commonly experience non-severe or mild hypoglycaemia. Depending on the duration of type 1 diabetes and the method of data collection, mild hypoglycaemia occurs on average 1-3 times per week. Multiple studies have shown that mild hypoglycaemia also commonly occurs following exercise, which contributes to the frequency of non-severe hypoglycaemia. Recurrent hypoglycaemia leads to blunting of counter-regulatory hormones which increases risk of further hypoglycaemia, including severe episodes and reduced awareness of hypoglycaemia. In addition, hypoglycaemia and fear of hypoglycaemia are well established barriers to exercise in people with type 1 diabetes. This data compliments epidemiological studies that show people with type 1 diabetes tend to exercise less than their peers who do not have diabetes. Despite hypoglycaemia being a recognized acute complication of physical activity in type 1 diabetes, regular exercise is recommended due to its multiple potential cardiovascular benefits. International guidelines recommend that people with type 1 diabetes, similar to healthy peers, undertake at least 150 min per week of moderate intensity aerobic physical activity, or at least 75 min per week of vigorous intensity aerobic physical activity. The aim of the body of research in this thesis was firstly to define the amount and type of exercise that is undertaken by people with type 1 diabetes under regular specialist care in a diabetes centre, and what percentage of non-severe or mild hypoglycaemia is related to exercise. Secondly, the research aimed to show whether intervention with an established educational online tool for people with type 1 diabetes, exT1D, can lead to a reduction in exercise-related hypoglycaemia. Chapter 3 was dedicated to a pilot study, undertaken to develop study procedures that would also be further employed in both the type 1 Diabetes Clinic Audit Survey as well as the randomised controlled trial, T1EX. It also served to aid the power calculation for the main endpoint of the T1EX trial. In Chapter 3 it is reported that most of the non-severe episodes of hypoglycaemia was related to exercise, defined as episodes of hypoglycaemia that occurred within 24 hrs of the onset of an exercise session. Those findings were seen in 5 adults with type 1 diabetes who at baseline undertook regular exercise, were physically fit and had good metabolic control with an average HbA1c level of 7.0% NGSP units. Those participants attempted to prevent their exercise-related hypoglycaemia mainly by consuming carbohydrates. This approach was particularly implemented for exercise duration longer than 60 min; however, the approach was typically not successful in preventing some degree of exercise-related hypoglycaemia. In addition, a positive relationship between self-reported fear of hypoglycaemia score and exercise-related hypoglycaemia was detected. In chapter 4 through use of series of established, validated questionnaires, it was found on subsequent analysis that most patients attending the type 1 diabetes clinic at the Royal Prince Alfred Hospital, undertook physical activity. However less than 50% fulfilled international guideline recommendations. Furthermore, in analyzing exercise type, it was found that people with type 1 diabetes who engage in weekly resistance training by self-report, as opposed to only aerobic exercise, had a particular profile as a group that included: a trend to greater fear of hypoglycaemia; being more confident in their overall diabetes self-management; and they were able to exercise for longer before experiencing an episode of severe, as well as non-severe, hypoglycaemia. This finding was reflected in an observational part of the randomized controlled trial. In the randomised controlled trial using the CGM generated hypoglycaemia data and actual undertaken exercise, participants who undertook resistance training were able to exercise for longer rather than their peers who solely undertook aerobic exercise before experiencing an episode of non-severe hypoglycaemia. As exercise commonly contributes to hypoglycaemia, a method to potentially reduced this complication was then studied. A commercial educational website, ext1d.com.au was developed for people with type 1 diabetes to improve glycaemia around exercise. Modules describe glucose physiology in the context of exercise and offer suggestions on glycaemia management. The main prospective study in this thesis, examined this pre-existing online tool in a randomised controlled trial. Chapter 5, described the type 1 diabetes and exercise (T1EX) trial, which was a randomised controlled trial with partial crossover of the control group into the intervention arm and related main outcomes. There was no significant reduction in exercise related hypoglycaemia, despite observed 37% reduction in exercise related hypoglycaemia compared with exercise session number in the intervention part of the RCT (primary end-point), and a median 50% reduction in the frequency of exercise-related hypoglycaemia in the intervention compared with Control. However, in the longitudinal study as pre-defined secondary end-points, a reduction from baseline in the frequency (43%, NS with p=0.088), and to a greater and statistically significant degree in the duration of exercise-related hypoglycaemia (71% reduction, p=0.03), was observed by the intervention. The overall reduction in hypoglycaemia duration, observed in the intervention group after the 5 weeks of the study, was sustained in a further 5-week time interval. These benefits in T1EX occurred with overall stable glycaemic control throughout the trial, as expressed by HbA1c and fructosamine levels, as well as an improvement in confidence in managing glycaemia around exercise following intervention by self-report. In post-hoc analysis, these benefits of a reduction in exercise-related hypoglycaemia were particularly seen in the 50% of participants who at baseline had the highest frequency of exercise-related hypoglycaemia (more than 3 episodes at baseline). These subjects collectively had a highly statistically significant reduction in hypoglycaemia number (p=0.002) and duration (p=0.004). In addition, they had significant reductions in nocturnal hypoglycaemia duration (p