COLUMBUS, OHIO — For patients with metabolic syndrome, the focus should be on the two “L” words: lifestyle and LDL.
That was the message from a talk given by former American Heart Association president Robert H. Eckel at a meeting on diabetes sponsored by Ohio State University. The term “metabolic syndrome” has become controversial since the September 2005 publication of a joint statement from the American Diabetes Association (ADA) and the European Association for the Study of Diabetes that called into question whether classifying the entity as a “syndrome” adds any clinical utility beyond its individual components (Diabetes Care 2005:28:2289–304).
With that debate still ongoing, Dr. Eckel was the lead author of a “call to action” from the ADA and the American Heart Association (AHA) in which both organizations expressed their strong commitment to prevention of cardiovascular disease and type 2 diabetes, and urged all health care providers to assess patients—especially those who are overweight or obese—for their CVD risk factors (Diabetes Care 2006;29:1697–9).
“The metabolic syndrome wasn't meant to be a global risk predictor for heart disease. It was meant to identify a cluster of risk factors that can be best modified initially by lifestyle,” said Dr. Eckel, professor of medicine and the Charles A. Boettcher II Chair in Atherosclerosis at the University of Colorado, Denver.
Although data conflict somewhat as to whether metabolic syndrome does in fact increase the risk for CVD and death, a recent meta-analysis of 43 cohorts in 37 longitudinal studies comprising 172,573 patients found that metabolic syndrome conferred an independent relative risk of 1.54 after adjusting for all known cardiovascular risk factors (J. Am. Coll. Cardiol. 2007;49:403–14).
In contrast to the disagreement on cardiovascular disease (CVD) risk, the data agree overwhelmingly on the benefits of lifestyle modification in patients with metabolic syndrome. Interventions that improve the quality of the diet, increase physical activity, and reduce weight often lead to improvements in a long list of cardiovascular risk factors, including reductions in waist circumference (a surrogate for visceral fat deposition), triglycerides, blood pressure, glucose, and inflammatory markers, along with increases in HDL cholesterol. “Seems like the perfect therapy to me,” Dr. Eckel remarked.
Still, diet specifics remain controversial. Although the key to weight reduction is clearly to expend more energy than is consumed, the importance of the carbohydrate/protein/fat ratio to the equation is still debated. Many people believe that low-carbohydrate plans such as the Atkins diet produce superior weight loss, but Atkins fared no better at 1 year than did the low-fat, high-fiber Ornish regimen or other popular diets such as the Zone diet and Weight Watchers when compared in a head-to-head study (JAMA 2005;293:43–53).
Data supporting the medical benefits of lifestyle modification include an analysis of the landmark Diabetes Prevention Program. That study found that weight loss via lifestyle modification was the predominant predictor of reduced diabetes incidence in 1,079 program participants aged 25–84 years (Diabetes Care 2006;29:2102–7). And in the first year of the Look AHEAD (Action for Health in Diabetes), intensive lifestyle modification resulted in an average 8.6% weight loss in 5,145 patients with type 2 diabetes, which was associated with a reduction in CVD risk factors and a reduced need for medication (Diabetes Care 2007;30:1374–83).
Yet, despite such strong evidence, an AHA survey of physicians found that fewer than 10% of cardiologists and fewer than 15% of family physicians even ask patients about their current diet and physical activity levels, let alone spend much time encouraging improvement in them. “As physicians we have to be engaged, informed, and passionate about lifestyle and how important it really is,” Dr. Eckel said.
Beyond lifestyle, medications that address the various components of metabolic syndrome can affect other components as well. The weight-loss drugs orlistat and sibutramine both also reduce waist circumference, glucose, triglycerides, and C-reactive protein. Statins, besides lowering LDL cholesterol, also raise HDL cholesterol.
Although data strongly support blood pressure and glucose as primary targets of therapy beyond lifestyle in people with metabolic syndrome, the strongest data are those that support LDL lowering in patients with and without diabetes. “Let's not lose the importance of focusing on LDL lowering in patients with metabolic syndrome, even though it's not a part of the clustering of components,” Dr. Eckel remarked.
'We have to be engaged, informed, and passionate about lifestyle and how important it really is.' DR. ECKEL