Medical Device Daily

From 1980 to 2000, deaths from coronary heart disease (CHD) in the U.S. fell by more than 40%, and almost half of this drop (44%) was attributable to reductions in major risk factors, a new study reveals published in the June 7 issue of the New England Journal of Medicine. The findings may come as a surprise because it has been widely assumed that any drop in CHD deaths is largely due to better treatment.

Earl Ford, MD of the National Center for Chronic Disease Prevention and Health Promotion, at the Centers for Disease Control (CDC; Atlanta) and his colleagues reported in an article titled “Explaining the decrease in U.S. deaths from coronary disease, 1980-2000, that their research showed that modification of risk factors such as blood pressure, lipid levels, and smoking by nonmedical means has had a much larger impact on deaths than modern surgical technologies such as angioplasty.

According to Darwin Labarthe, Director of the Division for Heart Disease and Stroke Prevention, National Center for Chronic Disease Prevention and Health Promotion, Coordinating Center for Health Promotion at the CDC, while it was uncertain what the outcomes would be in the U.S., there had been indications from studies around the world that modern medicine wasn’t the driving force in CHD reduction as has been assumed by many.

“This has been a consistent finding in similar analysis of a number of countries’ data,” Labarthe told Medical Device Daily. “While the advances in medical therapeutics and surgical techniques have clearly made important contributions, the lifestyle changes and the control of the risk factors are a major part of the overall strategy of prevention and reducing risk.”

He said that the importance of the risk factor prevention and risk factor control is underscored in the report, but in his opinion, is still underestimated. This is particularly evident when one realizes that for nearly 40% of people that have heart disease, death is the first symptom that there is a problem.

Enhancing preventive medicine could help, Labarthe said, “prevent deaths that occur so rapidly that there’s no opportunity to benefit from high tech surgical intervention or even long-term medication.”

Ford and his colleagues applied a statistical model, IMPACT, to data on the use and effectiveness of specific cardiac treatments and on changes in risk factors between 1980 and 2000 among U.S. adults aged 25 to 84 years old. The IMPACT mortality model has previously been validated in Europe, New Zealand, and China and was updated for this U.S. study.

During the two decades that the study evaluated there was a rapid growth in costly medical technologies and pharmaceutical treatments for coronary heart disease as well as substantial public-health efforts to reduce the prevalence of major cardiovascular risk factors. “Establishing the relative contributions of these two approaches is therefore of considerable interest,” the authors of the study observed.

The study found that the age-adjusted death rate (men and women age 25-84) for CHD fell from 542.9 to 266.8 deaths per 100,000 population among men and from 263.3 to 134.4 deaths per 100,000 population among women.

In 1980, a total of 462,984 deaths among people in this age group were recorded as due to coronary heart disease, according to the International Classification of Diseases, 9th Revision. In 2000, a total of 337,658 such deaths were recorded, according to the International Classification of Diseases, 10th Revision. However, had the age-specific death rates from 1980 remained in 2000, an additional 341,745 deaths from coronary heart disease would have occurred, the study showed.

About 47% of this decrease (About 159,330 deaths prevented) was attributed to treatments, with the largest contributions from secondary preventive therapies after myocardial infartction (MI) or revascularization (11%), followed by treatments for acute coronary syndromes (10%), heart failure (9%), and revascularization by CABG or angioplasty for stable or unstable disease, which together accounted for just 7% of the overall drop in deaths from CHD.

In contrast, reducing blood pressure and lipids by nonmedical means — primarily by dietary improvements —accounted for a much larger proportion of the drop in deaths: 20% and 24%, respectively. Other changes in risk factors that contributed to the fall in deaths were reductions in smoking prevalence (12%) and improvements in physical activity (5%).

In all, the changes in risk factors accounted for approximately 149,635 fewer deaths during the 1980-2000 timeframe.

The drop in deaths attributed to changes in risk factors was partially offset, however, by increases in body-mass index (BMI) and the prevalence of diabetes, which accounted for an increased number of deaths (8% and 10%, respectively), the study showed. “The deaths could have been 20% lower if it hadn’t been for BMI and diabetes,” Labarthe noted. If had not been for the increase in these two risk factors, the study found that there would have been a situation where improvements in risk factors would have accounted for two thirds of the reduction in CHD deaths and treatment only one third.

The authors recommended that: “Future strategies for preventing and treating coronary artery disease should therefore be comprehensive, maximizing the coverage of effective treatments and actively promoting population-based prevention by reducing risk factors.”

Underscoring the focus in the U.S. on utilizing the latest drugs and technologies at the expense of pushing preventive measures, Labarthe noted that only between 1% and 5% of total healthcare expenditures in the U.S. are earmarked for preventive measures. “Our society as a whole is substantially underinvested in the preventive measures that society tells us can clearly have a major impact,” he said. “The best message is [for patients to] get much more serious about the lifestyle changes that are needed and (enhance) the conditions that enable those people to make those changes.”