May 11, 2012

Century of scientific discovery beats down heart attack rates

Kaiser Permanente researcher Steve Sidney, MD, tests a CARDIA participant on a treadmill. KP Division of Research photo.

Contributed by Lincoln Cushing, Archivist and Historian

In 1772, Edward Jenner, an English physician, was the first to postulate that hardened coronary arteries in autopsies was a probable cause of heart disease. Photo courtesy of Jenner Museum in Berkeley, England.

In 1956, my grandfather died suddenly of a heart attack. He was 56. I never got to know him. Grandpa Barr, a life-long inhabitant of rural Iowa who had weathered the Great Depression and sent a son to war, didn’t know what hit him. He had no idea he had heart disease, and even if he had been diagnosed, his small town doctor had little in his black bag to prevent his early demise.

In the 1950s, physicians and researchers had no more than an inkling of how they could treat cardiovascular disease. In fact, physicians weren’t sure of the causes of heart attacks, and researchers were struggling to put together the heart disease puzzle.

Fifteen years later my mother told me she would probably die of a heart attack in her 50s like her father. Almost true to her prediction, she developed heart disease in her 60s. In her 70s she told me she was living on “borrowed time.” Maybe she was, but with lots of drugs, plenty of visits to the medical center and the installation of a pacemaker, she made it to the age of 87.

The difference between my mother’s fate and her dad’s is an amazing body of research and advances in technology that makes it routine in 2012 for doctors to be able to extend the lives of heart disease victims by decades.

A kernel of evidence emerges in the 18th Century

The earliest recognition of what might cause heart attacks was documented in 1772 when Edward Jenner, an English physician, noted hardening of the coronary arteries in the autopsy of a heart attack patient under his care.

“ ... after having examined the most remote parts of the heart, without finding any means for which I could account for his sudden death, or the symptoms preceding it, I was making a transverse section of the heart pretty near its base when my knife struck against something hard and gritty, as to notch it. I well remember looking up at the ceiling, which was old and crumbling, conceiving that some plaster had fallen down. But on further scrutiny the real cause appeared: The coronary arteries had become bony canals,” Jenner wrote to his colleague, Caleb Hillier Parry.

In 1938, O.F. Hedley, MD, a Philadelphia public health official, discussed Jenner’s letter in an article in the American Journal of Public Health (AJPH). “The opinion Jenner expressed concerning the progressive nature of the underlying changes was prognostically prophetic, for medical science still waits methods for preventing coronary artery disease or satisfactorily postponing its more serious consequences.”

Long journey to understanding heart disease

Many decades have gone by since Jenner first implicated atherosclerosis (hardening of the arteries) as a culprit in heart disease. In the intervening years, researchers have inched forward in their quest to bring down the heart disease death toll.

In 1921, heart disease became the leading cause of death in the United States, according to mortality data collected by the Census Bureau. New York's heart attack rate was soaring at the time.

In a 1927 AJPH article, William Munley, a New York physician, reported that between 1910 and 1925, New York City’s deaths from heart disease had increased by 50% percent – from 175 per 100,000 population to 266 per 100,000. He estimated that 2 million Americans were afflicted with heart disease at that time. The statistics had shifted so that atherosclerotic heart disease accounted for 40% of the deaths while rheumatic heart conditions made up 25%. (Syphilitic heart disease made up 10 percent with the rest in the category of unknown cause.) Rheumatic heart disease, thought to be the main cause of heart attacks and failure until the 1920s, had been largely conquered through public health efforts to eradicate rheumatic fever, which often left a damaged heart.

Munley wrote: “We have no established facts concerning the prevention of the degenerative types of heart disease. It is true that much has been written of the physical stress and nervous strain of the present-day (1927) mode of living as a factor in the production of high blood pressure and hardening of the arteries ... While no preventive methods are at present known for this type of disease, people can be taught the right way to live. Though we cannot cure this disease, we can hope to relieve some of the suffering produced by it and thus hope to prolong life.”

So that was medical researchers’ mission for the next 6 decades: find ways to treat coronary atherosclerosis and high blood pressure to prevent early death. Technical advances in the 1920s and 1930s gave birth to the first blood pressure monitor and the electrocardiogram (EKG), both useful diagnostic tools. Researchers also forged ahead to discover ways to prevent heart disease, and other chronic conditions, through exercise and dietary and lifestyle changes.

Federal government gets into the act

A wise advertiser suggested eating salad for good health as early as 1929.

In 1948, the federal government, recognizing heart disease as a growing threat to public health, sponsored the Framingham Heart Study, a compilation of the health data of thousands of ordinary people in Framingham, Massachusetts. Data collected initially from 6,000 residents was used to make the connection between the study group’s health, diet, medical history and lifestyle and the eventual development of heart disease. The now-legendary project has followed three generations and spawned over 1,200 research articles, shedding light on many aspects of heart disease.

In the early 1960s, the Framingham researchers published results that showed cigarette smoking, high cholesterol levels, high blood pressure and abnormalities in EKG results indicated increased risk for heart disease. In 1967, they found that physical activity reduced the risk of heart problems while obesity increased the probability.

In 1970, they published studies that identified high blood pressure and atrial fibrillation (uncontrolled fast heart rate) as risk factors for stroke. In 1976, they found menopause increased the risk of heart disease; in 1988, they learned that high levels of the “good” cholesterol HDL (from fats such as avocados, olive oil, fish oil and nuts) reduced the risk of heart disease.

KP researchers undertake key studies

Longshoremen queue up for their KP multiphasic health screening in 1961 on the San Francisco waterfront.

Meanwhile, other organizations, including Kaiser Permanente, were conducting studies of their own. In 1959, Kaiser Permanente joined with the Public Health Institute and UC Berkeley for the Child Health and Development Studies (CHDS), a collection of data from 15,000 East Bay pregnant health plan members from 1959 to 1967. CHDS scientists continue to use the data collected 50 years ago to study biologic, behavioral, genetic and environmental factors in early family life and how they affect the health of the subjects as adults.

In 2010, these researchers published a study that established a connection between preeclampsia (high blood pressure and protein in the urine) in pregnancy and heart disease later in life. Of the women who participated in the early study, 481 developed preeclampsia and 266 of them died of cardiovascular disease many years later. This link gives physicians and patients knowledge of an increased risk that can be ameliorated with preventive measures. CHDS researchers are taking the longitudinal study to a new level today by following up with the adult children whose mothers participated in the initial study.

In 1971, researchers in the California Department of Public Health and the University of California at Berkeley published an 18-year follow-up study of 3,263 Oakland and San Francisco longshoremen who participated in the Kaiser Permanente multiphasic (comprehensive health check-up) examinations in 1951. The study revealed that 350 of the participants — all male — had died of heart disease and 93 of stroke by 1970.

Researchers separated out the high- and low-risk populations and identified four categories associated with cardiac death: already having heart disease and/or high blood pressure, smoking one or more packs of cigarettes a day and being overweight. The study also found that the heart attack rate was less for men who had physically demanding jobs.

Total Health Project focuses on prevention

Kaiser Permanente South Sacramento Planning for Health newsletter graphic promoting a preventive medicine class, 1990.

By 1981 the understanding of what causes heart disease had progressed far enough to spur Kaiser Permanente founding physician Sidney R. Garfield to launch a study essentially to test patients’ willingness to change their lifestyle to prevent chronic disease. He invited new Kaiser Permanente members to complete a health self-assessment and to have a comprehensive physical at the experimental Total Health Center in Oakland. The participants were encouraged to avail themselves of expanded groundbreaking health education services to learn more about how to preserve their good health.

The Total Health Project gave rise to enhanced health education services throughout the KP health system so physicians could refer their patients to programs that could help them prevent disease and to manage chronic disease when it struck.

In 1985 the Division of Research (DOR, Oakland, CA) collaborated on a study of young adult men and women, Black and white, from Oakland, Chicago, Minneapolis and Birmingham, Alabama. The Coronary Artery Risk Development in Young Adults (CARDIA) followed 5,000 Americans who were 18 to 30 years of age in 1985-86 to middle age 20 years later.

The 20-year follow-up study showed that the participants gained an average of 30 to 35 pounds. Testing of the participants, now 38 to 50 years of age, showed that 18% had calcification of the coronary arteries (atherosclerosis, a precursor to cardiac disease).

Evidence of early disease was most common in those whose high fat diet and lifestyle increased their risk. The CARDIA researchers also found that individuals who continued to be physically active into middle age, particularly women, gained less weight over the years compared to those who were sedentary. In 1998, a Kaiser Permanente Division of Research team worked with UC San Francisco to study the usage and effectiveness of beta-blocker drugs prescribed for patients after an acute myocardial infarction (heart attack). The research team focused on 396 patients who took beta-blockers and compared their experience with the rest of the 1,050 study group. They concluded the use of beta-blockers, even in a lower dose than initially recommended, resulted in 38% fewer heart attack deaths.

Physicians associated with Kaiser Permanente’s Center for Health Research (Hawaii and Oregon) collaborated in studies in 1995, 1997 and 1999 to assess the success of the Dietary Approaches to Stop Hypertension (DASH) trial involving Americans with high blood pressure. Ethnically diverse study subjects followed one of three diets in the research carried out in four clinical centers across the country.

In the 1999 study, hypertensive participants who followed the DASH fruit and vegetable diet or the expanded combination diet, which also included whole grains, low-fat dairy, fish, poultry and nuts, experienced significant reductions in 24-hour blood pressure. The others who continued to eat a regular American diet of red meat, sweets and sugary soda saw no reduction in blood pressure.

2-pronged, aggressive approach to heart disease

In the past decade, Kaiser Permanente has made great strides in attacking heart disease. On the research front, studies have been done to validate drug therapies (i.e., beta blockers, aspirin, etc.) that stave off heart attacks and keep heart disease patients alive. This research includes a major study between 1999 and 2008 that showed a marked decrease in the number of KP patients who died following a heart attack.

In 2010, Kaiser Permanente's Division of Research published “Population Trends in the Incidence and Outcomes of Acute Myocardial Infarction,” in which they reported a 24 percent decrease in heart attacks among KP patients during the study period. They also reported a 62% decrease in serious heart attacks that do permanent damage in the same time frame. This decline in heart attacks contributed to the Kaiser Permanente Northern California region’s status as an island where heart disease is no longer the number one cause of death, as it is in the rest of the country.

Kaiser Permanente's second approach is prevention with a capital “P.” In the literature it’s sometimes called “primordial prevention.” This is defined as the individual’s commitment to improve his or her lifestyle to maintain a healthy weight, exercise and avoid heart disease. Kaiser Permanente’s “Thrive” campaign, launched in 2004, was initiated to highlight the health education and prevention programs that help KP members to keep their risk of chronic disease low.

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Farmers’ Markets sponsored in every Kaiser Permanente region, Community Benefit programs to reach out to underserved populations living in healthy food “deserts,” online Healthy Lifestyle programs, “Everybody Walks,” “Safe Routes to School,” and other exercise campaigns, as well as participating in community health promotion events, all contribute to Kaiser Permanente's Community Health Initiative.