The time lag prior to the rise in glucose requirements to maintain stable glycaemia during moderate exercise in a fasted insulinaemic state is of short duration and unaffected by the level at which glycaemia is maintained in Type 1 diabetes

AIMS

To determine the duration of the low hypoglycaemia risk period after the start of moderate-intensity exercise performed under basal insulinaemic conditions and whether this period is affected by the level at which glycaemia is maintained under these conditions.

METHODS

This was a prospective, randomized counterbalanced study. Eight participants with Type 1 diabetes (mean ± sd age 21.5 ± 4.0 years) underwent either a euglycaemic (5-6 mmol/l) or hyperglycaemic clamp (9-10 mmol/l) on separate days and were infused with insulin at basal rates and [6,6-² H]glucose while cycling for 40 min at 50% maximum oxygen consumption rate. The main outcome measures were the glucose infusion rates required to maintain stable glycaemia and glucoregulatory hormone levels, and rates of glucose appearance and disappearance.

RESULTS

During the first 20 min of exercise, the glucose infusion rate did not increase significantly, irrespective of the level at which glycaemia was maintained, but increased acutely between 20 and 25 min under both conditions. Maintaining higher glycaemia resulted in higher glucose infusion rate during, but not early post-exercise. With the exception of epinephrine, the glucoregulatory hormone levels and rates of glucose appearance and disappearance were similar between conditions.

CONCLUSION

Irrespective of the levels at which glycaemia is maintained, there is a 20-min low exogenous glucose demand period during which the exogenous glucose requirements to maintain stable glycaemia do not increase during moderate exercise performed at basal insulin level.

A 10-second sprint does not blunt hormonal counter-regulation to subsequent hypoglycaemia

AIM

To investigate whether a 10-second (s) sprint impairs the counter-regulatory response to subsequent hypoglycaemia.

METHODS

Nine people (five male, four female) with Type 1 diabetes, aged 21.1 ± 4.5 years, performed a 10-s rest or a 10-s maximum-effort sprint in random order on different days, while subjected to an euinsulinaemic-euglycaemic clamp. This was followed by a hyperinsulinaemic-hypoglycaemic glucose clamp 2.5 h later to induce hypoglycaemia for 40 min. At timed intervals, the counter-regulatory hormonal responses to hypoglycaemia were measured. Blood pressure, heart rate and hypoglycaemic symptoms were also assessed.

RESULTS

During the hypoglycaemic clamp, epinephrine, norepinephrine, growth hormone and cortisol levels increased significantly from baseline, and their responses were similar after both rest and sprint conditions. In particular, plasma epinephrine rose eightfold, from 197 ± 103 pmol/l to 1582 ± 1118 pmol/l after the rest condition, and from 219 ± 119 pmol/l to 1900 ± 898 pmol/l after the sprint condition.

CONCLUSION

A 10-s sprint is unlikely to blunt the subsequent hormonal counter-regulation to hypoglycaemia in individuals with Type 1 diabetes.

Safety and efficacy of the predictive low glucose management system in the prevention of hypoglycaemia: protocol for randomised controlled home trial to evaluate the Suspend before low function

INTRODUCTION

Innovations with sensor-augmented pump therapy (SAPT) to reduce hypoglycaemia in patients with type 1 diabetes are an ongoing area of research. The predictive low glucose management (PLGM) system incorporates continuous glucose sensor data into an algorithm and suspends basal insulin before the occurrence of hypoglycaemia. The system was evaluated in in-clinic studies, and has informed the parameters of a larger home trial to study its efficacy and safety in real life.

METHODS AND ANALYSIS

The aim of this report is to describe the study design and outcome measures for the trial. This is a 6-month, multicentre, randomised controlled home trial to test the PLGM system in children and adolescents with type 1 diabetes. The system is available in the Medtronic MiniMed 640G pump as the 'Suspend before low' feature. Following a run-in period, participants are randomised to either the control arm with SAPT alone or the intervention arm with SAPT and Suspend before low. The primary aim of this study is to evaluate the time spent hypoglycaemic (sensor glucose <3.5 mmol/L) with and without the system. The secondary aims are to determine the number of hypoglycaemic events, the time spent hyperglycaemic, and to evaluate safety with ketosis and changes in glycated haemoglobin. The study also aims to assess the changes in counter-regulatory hormone responses to hypoglycaemia evaluated by a hyperinsulinaemic hypoglycaemic clamp in a subgroup of patients with impaired awareness. Validated questionnaires are used to measure the fear of hypoglycaemia and the impact on the quality of life to assess burden of the disease.

ETHICS AND DISSEMINATION

Ethics committee permissions were gained from respective Institutional Review boards. The findings of the study will provide high quality evidence of the ability of the system in the prevention of hypoglycaemia in real life.

TRIAL REGISTRATION NUMBER

ACTRN12614000510640, Pre-results.