Top AHA Research Reports—

Promoting Studies Influencing Medical Care, Childhood Obesity, Clean Air

WALLINGFORD — Clinical studies that may influence medical care and research that demonstrates how science can be effectively applied in the real world top the list of heart disease and stroke advances from 2008, said Timothy Gardner, MD, president of the American Heart Association. The American Heart Association has been compiling an annual list of the top ten major advances in heart disease and stroke research since 1996.

“It’s always difficult to choose from among such a broad array of new discoveries,” Dr Gardner said. “This year we included not only novel work in fundamental or basic science, but also important clinical studies that we believe will influence medical care in the future. In addition, we have chosen a number of studies that demonstrate the effectiveness of science applied in the real world, from hospitals to schools to whole communities. These implementation studies are of increasing importance as we try to determine how best to translate basic and clinical science for the benefit of the public.”

Achievements in 2008 include:

*Breathing cleaner air — Smoke-free legislation and hospitalizations for acute coronary syndrome

Data regarding the dangers of firsthand smoke exposure is generally accepted, but the concept that secondhand smoke exposure can cause serious harm still meets resistance. This has made passing effective clean air legislation more difficult, though there has been substantial progress, with many states in the United States and several European countries passing smoke-free legislation.

Previous studies of the effects of such legislation in individual towns and cities, while positive, have been criticized by some for lack of controls and incomplete data collection. However, a study in 2008, addressing many of these concerns, makes a very strong case for this type of public health initiative. In Scotland, after smoke-free legislation covering all enclosed places was implemented, hospital admissions for acute coronary syndrome decreased by 17 percent.

This compared with only a four percent decrease in England, where there was no such legislation. The decrease in Scotland was highest in never-smokers, but there was also a smaller decrease in former smokers. Smokers had the lowest decrease, but still saw a 14 percent decline. A total of 67 percent of the decrease in hospital admissions involved nonsmokers, supporting the argument that protection for these individuals is an important benefit of this legislation, and that it should be extended more broadly.

*The acute care of patients with heart attack or stroke: Can we do better?

Because evidence-based therapy to improve heart attack and stroke outcomes was not being uniformly delivered in hospitals across the country, quality improvement programs were developed. Their goal was to facilitate the work of health care providers, and ensure that each patient receives the appropriate therapy.

Now, more than one million patients have been treated with the assistance of one of these programs, the American Heart Association’s Get With The Guidelines (GWTG), and the effect of these programs on delivered care is now being reported. Two studies, evaluating the GWTG — Stroke and the GWTG — Coronary Artery Disease (CAD) modules of GWTG, demonstrate that participation in hospital-based quality improvement programs such as GWTG is associated with substantially improved hospital performance.

*Type 2 diabetes: What is the legacy of intensive treatment?

The UK Prospective Diabetes Study has now followed patients with type 2 diabetes for ten years after the initial period in which the benefits of HbA1c (blood sugar) control by drug treatment were established. In 2008, follow-up data demonstrated that, while the improvement in HbA1c levels was lost after the first several years, the reduction in diabetes-related endpoints and microvascular disease continued, and over time, a significant reduction in heart attacks and deaths from any cause emerged.

This reinforces the benefit of good diabetes control in type 2 diabetes, adding importantly to the benefits demonstrated by the earlier Diabetes Control and Complications Trial. In contrast, in another section of the study, when the group in whom blood pressure was tightly controlled during the study was followed over the same ten-year period, the early reductions in any diabetes-related endpoint, including death, as well as in microvascular complications and stroke, was lost. This suggests that continued blood pressure control is critical to the maintenance of this risk reduction.

*The epidemic of childhood obesity: Can anything be done?

There is no lack of concern about the increasing numbers of children suffering from overweight and obesity, especially as the related development of other cardiovascular risk factors has become clear. Literally hundreds of programs have been developed to address this major public health problem, but very few have been adequately evaluated with hard clinical outcomes.

This past year a school intervention based on changes in policy, carried out in grades four to six in ten urban schools, was conducted. The intervention’s design incorporated school self-assessment, nutrition education, nutrition policy, social marketing, and parent outreach. Over a two-year period, this multicomponent program led to a 50 percent reduction in the incidence of overweight in the intervention schools compared with the control schools.

While there was no reduction in the incidence or prevalence of obesity, these results suggest that carefully designed, multicomponent programs can have an important impact on this serious epidemic.

*Selecting patients for prevention treatment

Substantial evidence demonstrates the effectiveness of lowering low density lipoprotein — LDL or “bad” — cholesterol to prevent repeat cardiovascular events, so-called secondary prevention. While lifestyle modification is important, and several types of medications can be used to lower the LDL, most patients are prescribed statins (HMG CoA reductase inhibitors).

For primary prevention to reduce the risk of an individual’s first event, the decision about whether to add medications to a healthy lifestyle is based on the patient’s overall risk of an event, assessed by a measure such as the Framingham risk score.

*Hypertension: Who is too old to treat?

It is well accepted that the effective treatment of high blood pressure is a very important factor in preventing cardiovascular complications such as stroke and heart failure. And while isolated systolic hypertension was a “normal” aspect of aging, we have also learned from the Systolic Hypertension in the Elderly Program study that control of this form of high blood pressure is also important. But questions remained about the very elderly, as they have usually been excluded from previous trials.

This year, a critical piece of evidence was added, when the HYVET (Hypertension in the Very Elderly Trial) was completed. The results of this important trial provide evidence that effective antihypertensive treatment, even in persons 80 years old or older, is beneficial in reducing the risk of cardiovascular events, and thus extends the group in whom prevention must be pursued.