UAMS Medical Center
LITTLE ROCK – In the largest study of its kind, J.L. Mehta, M.D., Ph.D., at the University of Arkansas for Medical Sciences (UAMS) has found that cholesterol-lowering drugs known as statins increased the life expectancy of elderly patients by an average of two years compared to non-statin users.
Mehta, director of the Division of Cardiovascular Medicine at UAMS and the affiliated Veterans Affairs Medical Center in Little Rock, tracked nearly 1.5 million patients who sought treatment in 10 medical centers of the South Central Veterans Affairs Healthcare Network of the U.S. Department of Veterans Affairs. The network includes the Central Arkansas Veterans Healthcare System on the UAMS campus.
The study’s results, which are particularly noteworthy because the statin users were at higher risk of death than the non-statin users, are published in the Oct. 1, 2006, issue of the American Journal of Cardiology.
About 350,000 patients, almost half over age 70, were prescribed statins, while 1.2 million patients were not. Statins were prescribed more often to elderly patients with a history of coronary artery disease, hypertension, diabetes, current smoking, and use of cardiovascular drugs.
“When we performed an extensive data analysis on survival, we were surprised to find that statin users actually lived an average two years longer despite the patients having more health risk factors and being older than non-statin users,” said Mehta, who is also the Stebbins Chair in Cardiology and professor of internal medicine and physiology and biophysics. “We did not expect that statin therapy would have such a profound impact on patients’ lives.”
The VAMC/UAMS statin study began in 2004 using data collected and administered by the VISN 16 Data Warehouse, a patient record system that was implemented in 1996 for the South Central Veterans Affairs Healthcare Network. The data analysis was done with the assistance of Zoran Bursac, Ph.D., M.P.H., of the Department of Biostatistics in the UAMS Fay W. Boozman College of Public Health.
The study is unique because of its size and because previous statin studies generally have excluded people over age 65, Mehta said. It also is the first study to show a graded relationship between risk factors and the life-saving effects of statins. The greater the morbidity/mortality risk score, the greater the statins’ benefit. For example, odds of death decreased by 22 percent for statin users with a risk score of one. Those with a risk score of five or six saw their odds of death decrease by 49 percent. Risk scores were based on factors such as history of diabetes, previous heart attack, tobacco use, hypertension and age.
“We know a lot about statins, but what eventually counts is how these drugs behave in patients,” Mehta said. “These data are very powerful.”
The study is continuing on statins’ effects on kidney function, which deteriorates as people grow older. Mehta also will research the drug’s potential prevention of diabetes and ability to keep high blood pressure from worsening.
Statins lower the level of cholesterol in the blood by reducing the production of cholesterol by the liver. Cholesterol contributes to the development of cholesterol-containing plaques within the arteries, the condition known as atherosclerosis, which reduces blood flow. When plaques rupture, a blood clot forms on the plaque, which restricts blood flow even more. When blood supply is not sufficient to the heart, the result is a heart attack. If the clot occurs on plaques in the brain, stroke is the result.
By lowering cholesterol levels, statins reduce the formation of new plaques and sometimes can reduce the size of existing plaques.