Am Fam Physician. 2004;69(4):952-953
The number of patients with type 2 diabetes who are treated with insulin is likely to increase rapidly. A variety of insulin compounds and regimens are available, which allows for individualized therapy but complicates the process of establishing the optimal routine for each patient. In addition to the medical challenges, patients may regard the initiation of insulin therapy as a sign that they have progressed to a more serious disease state. A review by McIntyre stresses the need to address all of the patient's concerns as well as the medical issues involved in initiating insulin therapy.
Insulin therapy is indicated in patients with type 2 diabetes who have hyperglycemic symptoms, particularly weight loss, despite lifestyle modifications and treatment with maximum tolerated dosages of oral hypoglycemic agents. A review of compliance and encouragement of diet, exercise, and lifestyle changes should be undertaken before major changes in therapy are made. Significant improvements in hemoglobin A1c level have been noted after a review of these issues in patients being considered for insulin therapy. Consideration also should be given to optimizing oral medications, such as changing to once-daily dosing to improve compliance. Other considerations are the use of metformin or thiazolidinediones to improve insulin sensitivity and slow the decline in β-cell function. Agents with complementary actions can be combined, such as adding acarbose (an α-glucosidase inhibitor) to maximum dosages of oral hypoglycemic agents. Despite these efforts, however, the natural progression of type 2 diabetes may result in loss of β-cell function and an increased probability that the patient will require insulin therapy.
A team approach can assist patients transitioning to insulin therapy. Patients and family members should receive significant education in glucose monitoring and insulin measurement and administration. They must be able to recognize, manage, and prevent hypoglycemic episodes. Weight gain is common but not inevitable after initiation of insulin therapy. It can be limited by attention to diet and exercise. Some patients have significant fear of needles and injections, and careful selection of the injection device and coaching in technique are essential.
Most patients are taking the maximum tolerated dosages of sulfonylureas and metformin when insulin therapy is initiated. In these patients, the best option often is to discontinue the sulfonylurea and begin a twice-daily mixed insulin (30/70) regimen. The initial daily dosage should be 0.5 U per kg, with two thirds given before breakfast and one third before the evening meal. Insulin dosages are titrated upward, based on blood glucose levels. Continuing metformin therapy may help prevent weight gain and reduce the total insulin requirement. A long-acting insulin may be added to the regimen.