The relationship between insulin dose and risk of heart disease in type 1 diabetes

The aim of the study was to look at the relationship between insulin dose and risk of cardiovascular disease (CVD) in type 1 diabetes (T1D). The main finding of the study was that higher insulin doses are associated with CVD risk factors but not with increased CVD events.

Patients with T1D have an increased risk of CVD (heart and blood vessel disease). However, some studies have suggested that high levels of insulin may be associated with CVD in type 2 diabetes (T2D). The main treatment of T1D is insulin. However, the relationship between the dose of insulin and CVD risk factors or CVD events in T1D is unknown. CVD events include death due to heart problems, heart attacks, strokes, angina, and heart failure.

This study included 1,441 patients with T1D. They were randomly assigned to receive either intense or standard insulin therapy. Intense therapy aimed to get fasting blood sugar level and HbA1c level (blood test measuring average blood sugar control over the past 3 months) as close to non-diabetic range as possible with high doses of insulin. The standard group were treated as normal with the goal of treatment being freedom from symptoms and clinical well-being. Patients were followed up for an average of 6.5 years.

High insulin doses were associated with a higher body mass index (BMI), higher heartbeat rate, higher amounts of fats in the blood and lower HDL (good cholesterol). These are all risk factors for CVD. It was calculated that a 0.1 unit per kilogram of body weight per day increase in insulin dose was associated with a 6% increased risk of CVD. However, there was no increased risk of CVD events.

The authors concluded that higher doses of insulin are associated with CVD risk factors. However, there was no increased risk of CVD events with high doses of insulin.