Hypoglycaemia and Cardiac Arrhythmias in Type 2 Diabetes

Hypoglycaemia and Cardiac Arrhythmias in Type 2 Diabetes

Twenty-one patients with insulin-treated type 2 diabetes with diabetic complications will be recruited to Part 1 of the study, a three-hour combined hyper- and hypoglycaemic clamp, along with a control group of twenty-one individuals with normal glucose tolerance matched for age, gender, and body mass index. Patients with type 2 diabetes will be scheduled for a three-week run-in period with LR and CGM prior to participation in Part 1. Only patients with a well-functioning loop-recorder and who can comply with CGM will be included. Patients with type 2 diabetes will continue in part 2 of the study, a one year observational study employing CGM and LR and clinical examination after 1, 3, 6, 9, and 12 months and an extended observation period of 2 years employing LR and clinical examination.

Inclusion Criteria:

Patients with type 2 diabetes

• Informed and written consent
• Type 2 diabetes diagnosed according to the criteria of the World Health Organization (WHO)
• Treatment with insulin
• Glycated haemoglobin A1c (HbA1c) ≤58 mmol/mol
• One or more clinical relevant complications to diabetes defined as: peripheral neuropathy with vibration perception threshold of > 25 volt determined by biothesiometry, moderate to severe retinopathy, nephropathy (creatinine >130 μmol/l and/or albuminuria), and/or macrovascular disease. Macrovascular disease is defined as coronary disease (stable angina pectoris or previous unstable angina pectoris or myocardial infarct), cerebrovascular disease (previous stroke or transitional cerebral ischaemia), and peripheral vascular disease (previous intermittent claudication or prior acute ischemia)
• Well-functioning LR during run-in period (acceptable readings judged by an arrhythmologist)
• Participation in the extended study

Healthy individuals

• HbA1c ≤42 mmol/mol
• Fasting plasma glucose ≤6.1 mmol/l

Exclusion Criteria:

Patients with type 2 diabetes

• Arrhythmia diagnosed prior to or at the time of inclusion
• Implantable cardioverter defibrillator (ICD) or pacemaker at the time of inclusion
• Severe heart failure (left ventricular ejection fraction <25%)
• Structural heart disease (Wolf-Parkinson-White syndrome, congenital heart disease, severe valve disease)
• Insulin naïve patients with type 2 diabetes
• Thyroid dysfunction (except for well-regulated eltroxine substituted myxoedema)
• Unable to comply with daily CGM during run-in period
• Anemia (male: hemoglobin < 8.0; female: hemoglobin < 7.0 mmol/l)

Healthy individuals

• Type 1 or type 2 diabetes
• Prediabetes (HbA1c >42 mmol/l and/or fasting plasma glucose >6.1 mmol/l)
• Family history of diabetes (type 1 og type 2 diabetes)
• Arrhythmia diagnosed prior to or at the time of inclusion
• ICD or pacemaker at the time of inclusion
• Severe heart failure (left ventricular ejection fraction <25%)
• Structural heart disease (Wolf-Parkinson-White syndrome, congenital heart disease, severe valve disease)
• Thyroid dysfunction (except for well-regulated eltroxine substituted myxoedema)
• Anemia (male: hemoglobin < 8.0; female: hemoglobin < 7.0 mmol/l)