Type 2 diabetes mellitus (T2DM), excess weight, and obesity are increasing in prevalence at alarming rates. 1–3 Concurrent with the increased prevalence is increased risk of morbidity and mortality. A healthy diet and exercise in conjunction with antidiabetes medications can help lower glucose concentration in patients with T2DM. Because these patients are at increased risk of cardiovascular (CV) morbidity and mortality, however, treatment strategies should address the CV risk factors, including blood pressure (BP), lipids, and body weight, as well as glycemic aspects of the disease.
To help clinicians manage the complex issues in treating patients with T2DM, this article presents an overview of patient and treatment perspectives relevant to overweight/obesity and CV disease (CVD). It includes an examination of the latest guidelines and algorithms for the management of T2DM, which continue to be updated and modified.
T2DM, WEIGHT GAIN OR OBESITY, AND CV RISK: A CHALLENGING TRIAD
Despite therapeutic advances in the diagnosis and treatment of diabetes and CVD over the last decade, the estimated number of persons in the United States older than 35 years with self-reported diabetes (with T2DM accounting for 90% to 95% of diagnosed cases) and CVD has increased from 4.2 million in 1997 to 5.7 million in 2005. 3,4 The CV risk for patients with T2DM who have not had a CV event such as a myocardial infarction (MI) is similar to that of individuals without diabetes who have had a prior MI. 5 Patients with T2DM have nearly double the mortality of those without the disease. 6 Adding to their risk, about 80% of patients with T2DM are overweight or obese, conditions associated with worsened insulin resistance and increased CV risk and disease burden. 7,8 Even a modest weight gain (5 kg) may increase the risk of coronary heart disease (CHD) by 30%, while associated changes in lipids and BP can increase the risk by another 20%. 9
It is as important to control CV risk factors as it is to control glycemia in patients with T2DM, and both are difficult to achieve. Data from a recent nationwide Norwegian survey showed that only 13% of patients with T2DM achieved study-defined target levels; ie, glycosylated hemoglobin (HbA1c) less than 7.5%, BP less than 140/85 mm Hg, and total cholesterol/high-density lipoprotein (HDL-C) ratio less than 4.0. 10
BENEFITS OF MANAGING GLYCEMIA, WEIGHT REDUCTION, AND CV RISK FACTORS
Several large studies, many ongoing, are generating data on the relationships among glycemia, weight reduction, and CV risk. It is well established that individuals with T2DM need aggressive risk factor reduction (glucose control, blood pressure management, and treatment of dyslipidemia) to optimize outcomes. However, characterization of the benefits of various components of risk factor reduction, particularly over many years, is only now occurring.
Results from the United Kingdom Prospective Diabetes Studies (UKPDS) showed the benefits and risks of pharmacologic glycemic control—essentially monotherapy with insulin or a sulfonylurea—compared with conventional dietary therapy in reducing diabetic complications in patients with newly diagnosed T2DM. In UKPDS 33, both insulin and sulfonylureas (intensive treatment) reduced the risk of microvascular end points (retinopathy, nephropathy) in patients whose median HbA1c was lowered to 7.0% at 10 years of follow-up, compared with patients who reached an HbA1c of 7.9%. However, intensive glycemic control did not translate into a statistically significant reduction in macrovascular complications, including MI, stroke, CVD, and death. Additionally, patients assigned to insulin had greater weight gain (+4.0 kg) than did patients assigned to receive the sulfonylurea chlorpropamide (+2.6 kg) or glyburide (+1.7 kg) ( P < .01). 11