The incidence of angina, heart attacks and coronary deaths dropped 20 percent in the U.S. between 1983 and 2011, according to a study by Duke investigators. But that good news is tempered by an additional finding that a large proportion of coronary heart disease can still be attributed to known risk factors, including high cholesterol, high blood pressure and smoking. "We have made progress in reducing incidence of coronary heart disease, but continued vigilance is needed to reduce the underlying causes of heart disease,” said Michael J. Pencina, PhD, director of biostatistics at the DCRI and senior author of a research letter published online Nov. 13 in the Journal of the American Medical Association. This research has been covered by numerous news outlets including Time, U.S. News and World Report, MSN News and several leading journals and newspapers.
Pencina and colleagues analyzed data from five large studies available through the National Heart, Lung, and Blood Institute’s BioLINCC program. The studies span a pivotal era in heart disease prevention, from the time of issuance of the first guidelines for diagnosis and treatment of high blood pressure in 1977 and high cholesterol in 1985, through numerous changes and adjustments to the guidelines.
Two groups of 14,000 patients were compared: one comprised of patients from an earlier period before 1995, when treatments, especially for high cholesterol, were not as wide-spread and effective; and the other from a more recent period after 1995.
“Despite our progress, we still have considerable room for improvement. The same risk factors we’ve been battling for years — smoking, high cholesterol, high blood pressure, and diabetes — are still responsible for a large proportion of heart disease,” said Ann Marie Navar, MD, PhD, assistant professor of cardiology at DCRI and lead author of the study. “The risk of heart disease in adults with diabetes declined over time, leading to a decrease in the fraction of heart disease attributable to diabetes. But this progress may be offset in the future if the prevalence of diabetes in the population continues to increase.”
In addition to finding a 20-percent decline in the incidence of coronary heart disease, the researchers found that the strength of association between high blood pressure, high cholesterol and smoking and the incidence of coronary disease remained similar over time. But this association decreased for diabetes, which could be attributable to better management of the condition.
Smoking, high blood pressure and high cholesterol continued to cause coronary heart disease at essentially the same rate over time.
“Risk factors still matter,” Pencina said. “While the event rates went down and it appears the interventions are working, that doesn’t mean we can ignore the risk factors. There are further gains that could be made if we were to prevent these conditions.”