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HDL-Atherosclerosis Treatment Study (HATS)

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: October 28, 1999
Last Update Posted: February 10, 2016
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by:
University of Washington
To measure the effects of lipid-lowering drugs and/or antioxidant vitamins on progression or regression of coronary heart disease as measured by quantitative angiography in patients with low high density lipoprotein (HDL) cholesterol.

Condition Intervention Phase
Cardiovascular Diseases Coronary Disease Heart Diseases Myocardial Ischemia Drug: simvastatin Drug: niacin Drug: antioxidants Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Factorial Assignment
Primary Purpose: Prevention

Further study details as provided by University of Washington:

Study Start Date: September 1994
Estimated Study Completion Date: February 2001
Detailed Description:


More than one-third of patients with coronary disease have "low" high density lipoprotein cholesterol (HDLc) levels (less than 35 mg/dl; United States 20th percentile) and "normal" low density lipoprotein cholesterol (LDLc) (less than 145; United States mean), a group for whom current treatment guidelines are not based on clinical trial data. Low HDLc levels are strong, independent predictors of cardiovascular disease and cardiovascular mortality risk, equally so for both men and women. This high coronary artery disease risk may be due to an imbalance between delivery of cholesterol into the arterial intima by LDL and its removal by HDL. Also, since HDL serve as antioxidants and cytoprotectants, an important HDL role may be to prevent LDL oxidation and thus limit macrophage-mediated intimal lipid accumulation or to prevent vascular cell toxicity. Recent epidemiologic, experimental, and clinical trial evidence suggests that a 15 mg/dl rise in HDL cholesterol would reduce coronary artery disease incidence and mortality by 30 to 70 percent and that antioxidant vitamins E, C, and beta-carotene might reduce coronary artery disease events and atherogenesis. The potential absolute benefit is much greater in those with existing coronary artery disease. It has also been shown that HDLc rises in response to exercise, smoking cessation, weight reduction, and monounsaturated fats.


Randomized, Phase III. Each patient was randomly assigned to a lipid-altering strategy or its placebo and to an antioxidant vitamin strategy or its placebo, in a 2 x 2 factorial design. The four groups were simvastatin-niacin plus an antioxidant vitamin cocktail; simvastatin-niacin plus vitamin placebo; antioxidant vitamins alone plus simvastatin-niacin placebo; or placebos for both strategies. All groups were counseled with respect to diet, exercise, and smoking cessation. The primary endpoint was the average change in proximal obstructive disease during the 2.5 year interval between baseline and the followup study. Secondary endpoints included the frequency of cardiac events, including cardiac death, confirmed non-fatal myocardial infarction, cerebrovascular accident, or revascularization by bypass or angioplasty for medically refractory unstable ischemia. The trial ended in August, 1999.


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Ages Eligible for Study:   35 Years to 68 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Men and women with low HDL cholesterol, with at least one 50% stenotic coronary lesion or three 30% stenotic coronary lesions. Women range in age from 35 to less than 68 and men from 35 to less than 63.
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00000553

Sponsors and Collaborators
University of Washington
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Bruce Brown University of Washington
  More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
ClinicalTrials.gov Identifier: NCT00000553     History of Changes
Other Study ID Numbers: 97
R01HL049546 ( U.S. NIH Grant/Contract )
First Submitted: October 27, 1999
First Posted: October 28, 1999
Last Update Posted: February 10, 2016
Last Verified: March 2005

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Coronary Disease
Coronary Artery Disease
Myocardial Ischemia
Pathologic Processes
Vascular Diseases
Arterial Occlusive Diseases
Anticholesteremic Agents
Hypolipidemic Agents
Molecular Mechanisms of Pharmacological Action
Lipid Regulating Agents
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Enzyme Inhibitors
Protective Agents
Physiological Effects of Drugs