Insulin therapy in patients with type 2 diabetes mellitus: Treatment to target fasting and postprandial blood glucose levels

Abstract

Background: Type 2 diabetes mellitus (DM) is a progressive disease characterized by both insulin resistance and β-cell failure, resulting in a decline in insulin secretion and increased blood glucose levels. Endogenous insulin replacement is eventually required to avoid the complications associated with poor glycemic control. Increasingly, evidence suggests that early introduction of insulin may slow the progression of type 2 DM, laying the foundations for long-term good glycemic control. Objective: The aim of this article was to review the advantages and disadvantages of various insulin-based treatment regimens and examine the best method of initiating insulin therapy in patients with type 2 DM. Methods: MEDLINE (1966–2006) was used to identify studies that reported on the use of insulin and insulin analogues for the treatment of DM. Key words used for the search included the following: insulin glargine, insulin detemir, insulin lispro, insulin aspart, insulin glulisine, regular human insulin, postprandial blood/plasma glucose, fasting blood/plasma glucose, and oral antidiabetic agents. Results : Although it is clear that both fasting blood glucose (FBG) and postprandial blood glucose levels contribute to glycemic control, evidence reviewed in this article suggests that FBG levels should first be normalized in newly diagnosed patients with poor glycemic control. Options for introducing insulin therapy include the use of 1 of the 3 broad classes of insulin preparations: basal, prandial, and premixed. The new basal insulin analogues may be the most effective method of targeting FBG. Indeed, insulin glargine and insulin detemir offer a number of advantages over more traditional preparations such as neutral protamine Hagedorn insulin and premixed insulin, including a reduced risk of hypoglycemia and less weight gain. Reducing the risk of these adverse effects is beneficial since they can prevent the initiation and appropriate titration of insulin. As the patient's condition deteriorates, prandial insulin can be added to the basal insulin analogue in a stepwise manner, eventually resulting in the use of a full basal-bolus regimen. Unfortunately, despite evidence supporting the early initiation of insulin therapy in patients with type 2 DM, many barriers to treatment exist, including the possibility of weight gain, a fear of injections, the belief that insulin regimens are complex, and skepticism over whether patients will follow the titration algorithms needed to achieve the stringent glycemic control targets. To ensure that insulin regimens are acceptable to patients and implemented by physicians, they should be as simple and efficient as possible. Recent studies have demonstrated the effectiveness of simple titration regimens for the initiation of basal insulin. Conclusion: A basal-bolus regimen can be tailored to the glycemic needs of each individual patient; the simplicity and flexibility of dosing may result in greater patient compliance and, thus, improved glycemic control.