One of the key challenges for people with T1D is managing the rise in their blood glucose after meals. Current clinical guidelines recommend that people with T1D calculate how much insulin to give based on the meal’s carbohydrate content. This assumes that the carbohydrate in meal is the only factor that contributes to increases in blood glucose. However, when people with T1D accurately carbohydrate count they frequently report unexplained high blood glucose levels after eating common meals like pizza or spaghetti bolognaise. These observations have led to a series of studies at John Hunter Childrens’ Hospital/ HMRI and Princess Margaret Hospital, Perth which demonstrated that fat and protein also cause increases in blood glucose and keep blood glucose levels higher for
Together, these studies have identified a clear need for people with T1D to give additional insulin for meals high in fat and protein. At present, however it is not known exactly how much additional insulin is required for these meals and when to give it.
For people with T1D there are two ways to give insulin; either using an insulin pump or by direct injection of insulin at mealtimes called multiple daily injections (MDI). In Australia and throughout the world MDI is the most common form of insulin therapy accounting for 88% of all T1D in Australia. Despite the popularity of MDI, to date there have been no studies looking at how to give insulin for meals high in fat and protein in people with T1D using this type of insulin therapy. One possible reason for this is that fat and protein have been shown to elevate blood glucose for up to 8-hours after a meal and, unlike insulin pump users those using MDI have no way of delivering insulin over an extended period of time.
The aim of this study is to identify an insulin dosing strategy for people with T1D using MDI that will effectively control their blood glucose levels after eating meals high in fat and protein.
To achieve this we will study the impact of;
- Increasing the total amount of insulin given for a meal high in fat and protein
- Extending the duration of insulin action by;
- Using a type of insulin that has a slower onset of action (Actrapid ®)
- Splitting the insulin dose ie giving a partial dose pre- meal and a partial dose post- meal."
Conjoint A/Prof Bruce King, Dr Carmel Smart