Intensive insulin therapy improves endothelial function and microvascular reactivity in young people with type 1 diabetes

Aims/hypothesis Macrovascular disease is an important cause of the increased morbidity and mortality rates associated with type 1 diabetes, and this vascular impairment begins in childhood. The aim of this study was to determine whether introducing intensive diabetes management [intensive insulin therapy (IIT) and 'Sweet Talk' text-messaging support] produces measurable improvements in endothelial function. Methods One hundred and twenty-six patients fulfilled the eligibility criteria (type 1 diabetes for >1 year; on conventional insulin therapy (CIT); aged between 8 and 18 years), of whom 92 enrolled. Patients were randomised to group 1, CIT only (n = 28); group 2, CIT and Sweet Talk (n = 33); or group 3, IIT and Sweet Talk (n = 31). Vascular assessments (including measures of endothelial damage, activation, dysfunction and oxidative stress) and HbA₁c were performed at baseline and repeated after 12 months of the study. Results Glycaemic control deteriorated in patients on CIT, but improved significantly in patients allocated to IIT (p = 0.007). IIT was associated with significantly greater improvements in E-selectin (p < 0.0001) than CIT (group 1, p = 0.026 and group 2, p = 0.053). Vascular responses to acetylcholine improved in patients on IIT (p = 0.017), but not in patients receiving CIT. These changes were all independent of HbA₁c level. Conclusions/interpretation IIT appears to be associated with improvements in vascular markers, independently of changes in HbA₁c, suggesting that IIT may confer vascular protection in addition to improving glycaemic control.