New Thoughts on Type 2 Diabetes Control
New Thoughts on Type 2 Diabetes Control
Abstract & Commentary
By Mary Elina Ferris, MD, Clinical Associate Professor, University of Southern California. Dr. Ferris reports no financial relationship to this field of study.
Synopsis:A review of large randomized clinical trials for type 2 diabetes controlling HbA1c as low as 6.5-7.0% showed many consequences, but uncertain benefits. A new approach to type 2 diabetes should include individualized HbA1c targets along with cardiovascular risk reduction reflecting patients' values and preferences, and caution is urged in using these HbA1c values as performance measures to indicate inadequate care.
Source: Montori VM, et al. Glycemic control in type 2 diabetes: Time for an evidence-based about-face? Ann Intern Med 2009;150:803-808.
This review utilized large trials (UKPDS, ADVANCE, ACCORD, and VADT), which measured clinical outcomes for persons with type 2 diabetes, comparing tight glycemic control (HbA1c < 7.0) to less intensive control. These trials are different from other studies that tested multifactorial risk reductions or the effects of different hypoglycemic agents on HbA1c. Adverse consequences of tight control included a 2- to 3-fold increased risk for severe hypoglycemia; the lowest HbA1c targets had the highest number of hypoglycemic episodes. At least 2% weight gain was also seen in most intensive control strategies. All-cause mortality and cardiovascular mortality were not reduced with intensive therapy.
Considering the burden involved in tight control, which may include frequent blood tests and medication adjustments, the authors argue that a change in approach is warranted to individualize glycemic targets and focus more attention on supporting well-being, healthy lifestyles, preventive care, and cardiovascular risk reduction. The authors suggest that keeping the HbA1c level between 7%-7.5% (corresponding to average serum glucose 150-160 mg/dL) is more feasible for most patients with type 2 diabetes.
Commentary
Diabetes treatment guidelines have recommended increasingly tight glycemic control to prevent serious consequences of microvascular disease in the kidneys and eyes, and macrovascular disease in the heart and brain. However, as this review article points out, when cardiovascular outcomes are analyzed, the benefit is not clearly proven. More than 50% of the mortality in type 2 diabetes is from CV complications. Another meta-analysis of type 2 diabetes tracking CV effects found that lowering blood pressure and lipid levels resulted in more benefit than lowering glucose levels.1 The adverse effects of this tight glycemic control, including weight gain and hypoglycemia, can be significant, along with major costs to both patients and the health care system.
Although major organizations continue to recommend tight control to prevent microvascular and neuropathic complications for both type 1 and type 2 diabetes, they recently acknowledged that less stringent HbA1c targets "may be appropriate" in patients with limited life expectancy or extensive comorbid conditions.2 Patients with a history of severe hypoglycemia, those with uncontrolled diabetes despite multiple attempts, or those who already have advanced diabetes complications are allowed a more relaxed approach. Dare we hope that this knowledge will be incorporated when our patients' HbA1c levels are used as quality measures of our "performance"?
References
1. Huang ES, et al. The effect of interventions to prevent cardiovascular disease in patients with type 2 diabetes mellitus. Am J Med 2001;111:633-642.
2. Skyler JS, et al. Intensive glycemic control and the prevention of cardiovascular events: Implications of the ACCORD, ADVANCE, and VA Diabetes Trials: A position statement of the American Diabetes Association and a Scientific Statement of the American College of Cardiology Foundation and the American Heart Association. J Am Coll Cardiol 2009;53:298-304.
A review of large randomized clinical trials for type 2 diabetes controlling HbA1c as low as 6.5-7.0% showed many consequences, but uncertain benefits. A new approach to type 2 diabetes should include individualized HbA1c targets along with cardiovascular risk reduction reflecting patients' values and preferences, and caution is urged in using these HbA1c values as performance measures to indicate inadequate care.Subscribe Now for Access
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