Obesity may hinder optimal control of blood pressure and cholesterol

Edmonton – Obese patients taking medications to lower their blood pressure and cholesterol levels are less likely to reach recommended targets for these cardiovascular disease risk factors than their normal weight counterparts, according to new research presented at the 2009 Canadian Cardiovascular Congress hosted by the Canadian Cardiovascular Society and the Heart and Stroke Foundation of Canada.

Dr. Vineet Bhan, a resident at the University of Toronto, sought to determine whether there were differences in reaching guideline-recommended targets for blood pressure and cholesterol levels according to body mass index (BMI) in a large number of individuals deemed to be at high risk for heart disease and stroke.

"In Canada, these high risk patients frequently do not reach their blood pressure and cholesterol targets," says Dr. Bhan. "The goal of our study was to see if obesity could be a factor."

He says that other studies have looked at obese individuals in the general population and found they were more likely to have high blood pressure, high cholesterol, and diabetes. "This, to our knowledge, is the first study looking at patients with established cardiovascular disease who are on treatment to see how obesity relates to the control of these risk factors," he says.

The study recruited 7,357 high risk patients who had a history of coronary artery disease, cerebrovascular disease, peripheral vascular disease, or diabetes plus additional cardiovascular risk factors from nine Canadian provinces. This observational study, based on two outpatient registries, took place from 2001 to 2004, recruiting 95 per cent of the patients from family physician offices. The registries were led by senior co-author, Dr. Shaun Goodman, and coordinated by the Canadian Heart Research Centre.

"Although a direct cause-and-effect relationship cannot be proven, our data would suggest that pharmacologic treatment alone without achieving optimal weight may not be adequate," says senior author, Dr. Andrew Yan. "This is a potentially important message to get across to clinicians, especially primary care physicians who are on the front line managing these high risk patients in the long term."

Patients were classified into three groups according to their BMI:

• normal weight (BMI <24.9)
• overweight (BMI 25 – 29.9)
• obese (BMI>30)