Insulin replacement therapy is essential for anyone with type 1 diabetes. Most patients with gestational or type 2 diabetes may also require insulin. The goals of insulin therapy are: to achieve optimal glycemic control without causing hypoglycemia or excessive weight gain and to minimize the impact on lifestyle. The therapeutic goals should be individualized according to patients age, disease duration, complications, comorbidities, lifestyle, and expected survival.
Selection of insulin regimens depends on residual endogenous insulin or insulin resistance, glucose control, and daily activities. The later insulin therapy is initiated, the less likely that target HbA1c will be achieved.
Insulin therapy is not without challenges. Patients and/or physicians resistance to insulin need to be overcome. As a consequence, starting and adhering to therapy has been difficult for both sides. Generally insulin analogs are not superior to human insulin in achieving glycemic control. However, the risk of hypoglycemia is lower, and they provide more flexibility.
There is no right way to initiate insulin therapy but there are several options and some guidelines derived from clinical trials. Insulin regimens for type 1 diabetes patients consist of basal-bolus components. The initial dose can be calculated 0.30.5 IU/kg per day given as 50% basal and 50% bolus in divided doses before meals. Carbohydrate counting and correction insulin doses may help to achieve better glycemic control.
The initial dose for basal insulin in patients with type 2 diabetes is usually 0.20.3 IU/kg per day. If glycemic control is not achieved with basal insulin alone, intensification of insulin therapy with addition of a regular or rapid-acting insulin prior to meals is indicated. Alternatively, a premixed biphasic formulation can be used before breakfast and dinner.
Insulin pump therapy may provide more flexible daily life with less frequency of hypoglycemia in most patients with type 1 and in some with type 2 diabetes.