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April 14, 2008
Benefits From Lower Cholesterol and Blood Pressure Targets
Lower cholesterol and blood pressure target levels may help adults with type 2 diabetes to prevent or even reverse hardening of their arteries, according to new research.
An estimated 21 million Americans have diabetes and 284,000 die from it each year, with 65% percent of these deaths related to cardiovascular causes. Hardening of the arteries, also known as atherosclerosis, is the main cause of heart and blood vessel disease.
NIH’s National Heart, Lung and Blood Institute (NHLBI) supported a 3-year study in people with diabetes to compare treatment targets for LDL ("bad") cholesterol and systolic blood pressure levels—both key risk factors for heart disease. The participants were 499 American Indians 40 years or older who had diabetes, high blood cholesterol and high blood pressure but no history of heart attack or other evidence of heart disease. The participants received medical care from the Indian Health Service, and medications were donated by First Horizon Pharmacy, Merck and Co., and Pfizer, Inc.
About half the participants were asked to lower their LDL cholesterol and blood pressure to standard levels (100 mg/dL LDL cholesterol and 130 mmHg systolic blood pressure), while the other half aimed for more aggressive lowering (70 mg/dL LDL cholesterol and 115 mmHg systolic blood pressure). Doctors examined the participants every 3 months and added or adjusted medications to help them achieve their goals. The participants were also encouraged to adopt lifestyle approaches, such as following a heart-healthy eating plan, being physically active and not smoking.
To determine the effect of treatment, the researchers used ultrasound to measure the thickness of the carotid (neck) artery—an indication of atherosclerosis. They also measured the size and function of the heart's main pumping chamber. Enlarged hearts are known to be predictors of increased heart attack and stroke risk. The results appeared in the April 9, 2008, issue of the Journal of the American Medical Association.
On average, participants in both groups reached and maintained their target goals for blood cholesterol and blood pressure levels. Over the 3 year follow-up period, the carotid-artery thickness increased slightly in the standard group, but regressed in the aggressive treatment group, indicating a partial reversal of atherosclerosis. By the end of follow-up, thickness measurements in the aggressive treatment group were significantly lower than in the standard treatment group. Heart size decreased in both groups, but the change was greater in the aggressive treatment group.
"These encouraging findings from SANDS suggest that more aggressive blood pressure and cholesterol targets than those currently recommended in patients with diabetes may reduce their future cardiovascular risk," said Dr. Jerome L. Fleg, a coauthor of the paper.
However, the study didn’t uncover direct evidence that these more aggressive targets could reduce the numbers of heart attacks and other cardiovascular events. These numbers were lower than expected and similar in both groups. The study wasn’t designed to reliably detect a difference in such events. Longer term follow-up, along with studies in other populations, will be needed to confirm the clinical benefits of these lower targets.