The following clinical issues were deduced from Marian's medical history, physical examination findings, and laboratory test results. She had uncontrolled T2DM and obesity with hyperlipidemia, though her blood pressure appeared to be controlled. She had distal sensory neuropathy and background retinopathy, as well as stage 3 chronic kidney disease. She was menopausal and had low bone mass.
Marian was currently taking two oral agents, but her T2DM remained uncontrolled. How should her therapy be advanced? Many options were available, including sulfonylureas, meglitinides, AGIs, DPP-IV inhibitors, incretin mimetics, and basal insulin. The strategy for making such therapeutic decisions is based on data showing that oral agents and exenatide lower HbA
1c levels by approximately 1% to 1.5%. When medications are combined, an additional 1% reduction in HbA
1c levels is usually achieved for each additional agent. Insulin has an unlimited capacity to lower HbA
1c levels.
2,3
In light of these considerations, how is the physician to decide when to add a new oral antidiabetes agent to a patient's treatment regimen or when to advance to insulin therapy? The basic rationale for making such a decision can be described as follows. If the addition of a given medication can be expected to reduce the patient's HbA1c level by 1%—and if this 1% reduction reaches the treatment goal for that patient—then that medication should be used. However, if the expected 1% HbA1c reduction from a given medication is not enough to reach the treatment goal for that patient, then the medication should not be used. In that case, insulin therapy should be started.
The Texas Diabetes Council (TDC)
Diabetes Tool Kit, which is posted on the Texas Department of Health Services Web site, includes an algorithm (Appendix)
4(p5.1) that can be used for making decisions on glycemic control for patients with T2DM. This decision algorithm, which we use at the Texas Diabetes Council, is more aggressive than that presented by Nathan et al.
5 Our goal is to achieve an HbA
1c level of less than or equal to 6%—provided that this level can be achieved without hypoglycemia. We want the fasting self-monitored blood glucose level to be less than or equal to 100 mg/dL, and the 2-hour postprandial self-monitored blood glucose level to be less than or equal to 140 mg/dL. In addition, medical nutrition counseling and an exercise program may be incorporated into the patient's treatment plan as part of the initial intervention.
Initial pharmaceutical intervention, as presented in the TDC algorithm,4(p5.1) consists of dual therapy if HbA1c levels are greater than or equal to 7.5%. (Monotherapy may be considered when a patient has an HbA1c level less than 7.5%.) Dual therapy options include various combinations of metformin, meglitinide, sulfonylureas, AGIs, DPP-IV inhibitors, TZDs, exenatide (an incretin mimetic), and insulin. If at the 3-month follow-up the patient's HbA1c level is less than 1% above goal, a third oral antidiabetes agent or exenatide is added to the treatment regimen. If at the 3-month follow-up that patient's HbA1c level is greater than 1% above goal, insulin is added as a third agent.4(p5.1)