Cardiovascular Disease in Women: Myths and Facts about a Silent EpidemicCHAPTER 1

Let us start by examining some statistics about heart disease in women in the United States.

Each year on an average 43 million American women are affected by heart disease. It roughly translates into heart disease killing one woman per minute. Center for Disease Control (CDC) data indicate that heart disease is the leading cause of death among women in the United States, killing 292,188 women in 2009—i.e. one in every four female deaths.

Since the last scientific statement on this topic in 1993, when the gender gap in various aspects of CVD was brought to light, a lot of attention has been given to a better appreciation of the influence of gender on heart disease and its management. In spite of that effort, however, important gaps in knowledge remain.

Heart disease in women presents a decade later as compared with men. But as women have a higher likeli­hood to survive longer, the death rates in women due to CVD tends to be equal or higher as compared with the men.¹

Also, as indicated by the Framingham Heart study, two- thirds of the women who had sudden cardiac death had no previous symptoms. Since majority of the women never make it to the hospital, presumably because of the lack of awareness of their heart symptoms, raising awareness of heart disease in women and directing the focus on primary prevention seem to be the best approach.

Cardiovascular disease has been the leading cause of death among women worldwide. It has been shown very well in the data presented by World Health Organization (WHO) in 2011. The organization studied the 10 leading causes of death among women in the countries with different income levels. The results are outlined below (Figs. 1A to E).

It is evident from the above-mentioned data that heart disease is the leading cause of death in women around the globe, regardless of the level of income.

Because of the worldwide extent of this health problem and its implications on the world health economics, in 2010, the WHO launched a worldwide effort to draw urgent attention to the number one killer for women. WHO Assis­tant Director-General Dr. Catherine Le Gales-Camus poin­ted out that.

“Although most women fear cancer, particularly breast cancer, they do not make the same efforts to safeguard themselves from heart disease, which is eminently preven­table.”

As Dr. Le Gales-Camus has stated, heart disease is the most common cause of fatality in women everywhere. However, in spite of clear evidence, most women still con­sider breast cancer as their number one threat.

We, as physicians, know that the anatomy and physio­logy of the heart is the same in men and women. Then, we wonder, why would there be a difference in heart disease in men and women at every step from the diagnosis to prognosis.

The differences in heart disease in men and women are due to the differences in the perception and presentation of the disease which then leads to the differences in the treatment and follow ups. These in turn ultimately result in the differences in prognosis and survival.

Let us examine some of the common myths that women and communities harbor about heart disease.

Myth—Heart disease is a man’s disease.5

Fact—Heart disease kills more women than men. Since 1984, each year more women have died of heart disease than men (Fig. 2).

Since 1984, women have outnumbered men in cardio­vascular mortality, and the gap continues to widen each year. Yet only one in five women thinks that heart disease is a real threat to them.¹

Despite increased awareness over the past decade, only 54% of women recognize that heart disease is their number one killer² (Fig. 3).

Myth—Breast cancer kills more women than heart disease.

Fact—Most women perceive breast cancer as their biggest threat and are diligent about their yearly breast examination and mammograms. However, the fact is that heart disease kills more women than all cancers combined. Studies show that on an average one in 25 women will die of cancer and one in two women will die of heart disease.¹

Myth—Heart disease is a disease of old men.

Fact—Increased incidence of smoking and use of birth control pills have increased the incidence of heart disease in women under 55 years of age. More than 50% of myocardial infarction (MI) in women is attributable to smoking.

Although the prevalence of smoking has been declining in the United States, the rate of smoking cessation is lower in women than men;¹ and after 2000, smoking rates have been higher in women (23%) than men (20%).³

The increased prevalence of smoking and the increas­ing trend of smoking particularly in young women have definitely contributed to the higher rates of CVD and cardiac deaths in women. Deaths of young women have significant implications on the families and economics alike. Smoking also increases their risk for hypertension.

A Norwegian study conducted by Meyer et al.⁴ demons­trated that smoking significantly increases cardiovascular and stroke risks in all the age groups in the 54,000 patients studied over three decades. However, it also showed that women who smoked had a higher incidence of cardio­vascular mortality and morbidity as compared with the men who smoked.⁴ The longitudinal study showed that two-thirds of the men who smoked had CVD, whereas half of the women who smoked suffered with cardiovascular disease (Fig. 4).

Another variable known to have increased the risk of heart disease in women is the lack of physical activity leading to the increased incidence of obesity. The preva­lence of obesity has increased steadily in women over the last two decades; and according to the 2007 estimates from the National Center for Health Statistics of the Center for Disease Control and Prevention, 60% of the adult women in the United States are overweight. Just over one-thirds of the overweight adult women are obese.⁵ In the last decade, approximately 34 million American women are classified as obese. Obesity, particularly abdominal obesity, is an important risk factor for CVD in women.^6,7 The figure below (Fig. 5) illustrates the CDC data on obesity trends among the adults in the United States in 2011–2012.⁸

Age-adjusted prevalence of obesity, by sex and age group, among adults at the age of 20 years and over: United States, 2011–2012.6

Increased prevalence of obesity has translated into increased risk of type two diabetes, which then increases the risk of heart disease, several folds.⁹ Diabetes is asso­ciated with a threefold to sevenfold elevation in coronary heart disease risk among women, compared with a twofold to threefold elevation among men; this gender-based difference may be because of a particularly deleterious effect of diabetes on lipids and blood pressure in women.⁵ Approximately 50% of the deaths in patients with type two diabetes is usually due to ischemic heart disease.¹⁰

In addition to the above-mentioned misperceptions, the symptoms of heart disease in women could be atypical. In addition to the traditional symptom of chest pain, women present with shortness of breath as a common presenting symptom. Other common symptoms are jaw or shoulder pain, dizziness, nausea, unexplained fatigue, or flu like symptoms.¹¹ Obviously these symptoms are vague and so a lot of women tend to ignore them and do not seek medical attention. Because of the ambiguous and atypical nature of the symptoms, they are likely to be ignored by the healthcare professionals as well. So, it comes as no surprise that the Framingham Heart Study revealed that two-thirds of the sudden cardiac deaths occurred in women with no “known” previous symptoms as compared with only half of the sudden deaths in men.¹ The 2012 statistical report from the American Heart Association (AHA) confirms the same finding.¹²

As for physicians, most of our practice guidelines and textbooks use data obtained in major clinical trials. Since women were involved in less than 25% of clinical trials, the data derived from them comprised of symptoms mostly of men, which then became the basis of traditional medical teaching and practice guidelines. As a result of that, physicians also did not identify and associate the above-mentioned symptoms with heart disease.

This gap in acknowledging symptoms of heart disease by patients and physicians has led to delays in diagnosis and seeking and delivering care by patients and physicians alike. So, it is no wonder that more women than men have cardiac arrest as their presenting symptom. It may explain why treatment is less likely to reduce death rate in women as most of them never reach a hospital.¹³ However, a recent review of literature about the evaluation of chest pain in women suggests that it is advisable to stratify patients in low-, intermediate-, and high-risk categories based on their cardiovascular risk factors, which will then guide the physician to seek appropriate diagnostic measures in a cost-effective manner.¹⁴ The 2011 updated effectiveness-based guidelines for primary and secondary prevention of CVD in women provide a very helpful algorithm for the workup to evaluate cardiovascular risk in women. This flow diagram is illustrated in the chapter by the same authors about the prevention of heart disease in women.¹⁵ 7

Heart disease in women presents a decade later as compared with men. As a result, women have more com­orbidities such as hypertension, diabetes, and hyper­lipidemia among others. This puts them at a higher risk for having a more complex clinical picture at the time of presentation and makes them more likely to have com­plications. Sometimes, the advanced and diffuse nature of the disease at presentation can limit the treatment options for the physicians.

The NIH study performed in 2012 shows a clear gender gap in the treatment of heart disease. The study indicates that for a variety of reasons women get less invasive treatment as compared with men.¹⁶ They are less likely to be offered with less-invasive therapy, and when offered, they are also more likely to decline the invasive treatment. If they undergo invasive procedures, they are more likely to have complications. After cardiac surgery, they are less likely to opt for rehab and are less likely to follow up.

These findings were almost replicated in a French study by Leurent¹⁷ of the Centre Hospitalier Universitaire in Rennes, France. Compared with men, women had a significantly higher rate of intrahospital mortality from MI at 9% versus 4.4% (P <0.0001). The study further identified the lack of timely aggressive treatment in women. Women also had a significantly longer median delay between onset of MI symptoms and calling for medical assistance (60 versus 44 min, P <0.0001). Female patients also had significantly more STEMI (S-T elevation myocardial infarc­tion) complications than men, including atrial fibrillation (7% versus 3%, P <0.0001). Leurent et al.¹⁷ also found that women were less likely to be discharged on recommended therapies than men:¹⁷

All of these factors translate into worse prognosis for women. They have higher fatality rate than men with the first MI. It is very interesting to see how the gender gap continues through the course. In the Framingham study and the more recent Multicenter Investigation of the limitation of Infarct Size study, women have been shown to have higher in-house mortality rate (13%) as compared with men (7%). By the first year after MI, the mortality was 44% in women as compared with 23% in men. By the second year, the gap continues, as mortality in women was 36% as compared with 21% in men.¹⁸ Women were also more likely to have subsequent cardiac events as compared with men.¹⁹

The data from the Myocardial Infarction Triage and Intervention registry also indicate that the gender gap in mortality in patients presenting with acute MI can be attributable to women receiving less-acute coro­nary interventions.^20,21 Similar findings were noted in a community study—Atherosclerotic Risk in Communities study.²²

A national survey shows that women are also less likely to enrol in cardiac rehabilitation after MI (6.9% versus 13.3%) and coronary artery bypass surgery (20.2% versus 24.6%) than men.²³ In addition to lower attendance rate, dropout rates from cardiac rehabilitation are also higher in women than men.²⁴

World Health Organization and the Indian Council of Medical Research collaborated to study heart disease in women.³ The study showed that urbanization in deve­loping countries has added several new variables to the traditional risk factors. As more women are entering the office work force, it has led to a lack of physical activity and an increased consumption of fast food and restaurant cooked food, which tends to have higher caloric content, which can translate into weight gain. Other factors that may increase cardiovascular risks are increased prevalence of smoking, rise in the use of birth control measures, and consumption of alcohol. All of these factors have contributed to the increased risk of heart disease in the urban women population in the developing countries.

In 1997, the AHA commissioned a survey to study the awareness of heart disease in women and the health­care community. The study identified and recognized a significant gap and lack of awareness about heart disease in women in the general population and healthcare providers alike.²⁵ “This is a missed opportunity,” said Lori Mosca, MD, MPH, PhD, lead author of the study. “Habits established in younger women can have lifelong rewards. We need to speak to the new generation, and help them understand that living heart healthy is going to help them feel better, not just help them live longer. So often the message is focused on how many women are dying from heart disease, but we need to be talking about how women are going to live—and live healthier.”

As a result of this gap, in 2003, AHA started the “Go Red for Women” initiative. The purpose was to raise awareness of heart disease in women, physicians, and communities. 8

With WHO recognizing the impact of heart disease in women as a preventable global issue, many other countries have started taking measures to evaluate this problem at their national level.

Heart disease is a threat to women and their families across the globe. As is evident from the data presented here, it is mostly preventable. Because of the enormous social and economic implications of heart disease in women, more countries need to dedicate resources to raise awareness of heart disease in women and physicians alike, so that measures can be taken to stop this silent epidemic.