Progress in heart failure: Some good news, some bad Michael W. Rich, MD

Cardiology Review® Online, March 2004, Volume 21, Issue 3

In the past 30 years, heart failure has emerged as a major public health problem in the United States and many other countries. This is in large part due to the progressive aging of the population and to improved survival among persons with hypertension and coronary artery disease, the two leading causes of heart failure in North America and Europe.

Nearly 5 million Americans have clinical heart failure, and more than 500,000 new cases are diagnosed each year.1 As a result, heart failure is the leading cause of hospitalization in the Medicare age group and is the most costly diagnosis-related group by a factor of 2. Women account for approximately 55% of all heart failure hospitalizations, and more than 50% of heart failure admissions occur in persons age 75 years or older.2

As concisely articulated by Drs. Wells and Little (page 14), the rise in the incidence of heart failure has been appropriately accompanied by intensified research, and major advances in the diagnosis and treatment of acute and chronic heart failure have occurred during the past two decades. Without question, these advances have led to substantial improvements in the prognosis and quality of life for many such patients, particularly those younger than 75 years whose heart failure is a result of impaired left ventricular systolic function. Unfortunately, such patients comprise less than one half of the total heart failure population. Thus, it is germane to ask: to what extent has recent progress in heart failure affected the epidemiology and clinical outcomes on a population-wide basis?

From 1979 to 2000, hospitalizations for heart failure in the United States increased by a factor of 2.65, from 377,000 to 999,000.1-3 In addition, several studies indicate that heart failure incidence has decreased slightly or remained unchanged during the past several decades,4,5 despite the emergence of new drug classes, such as angiotensin-converting enzyme (ACE) inhibitors and HMG-CoA reductase inhibitors (statins), which have been shown to reduce the incidence of heart failure in high-risk populations.6,7 Even more telling are a se-ries of studies reported during the past 20 years indicating that improvements in heart failure care have had virtually no impact on rehospitalization rates among elderly heart failure patients (table).8-14 Furthermore, although both age- and gender-adjusted mortality rates have declined modestly, the absolute number of deaths attributable to heart failure continues to rise.5,15

Why is it that the dramatic reductions in mortality and hospitalization rates reported in clinical trials (typically between 25% to 40%16) are not being realized in the broader heart failure population, despite the fact that authoritative, evidence-based guidelines for heart failure care have been widely promulgated? First, for reasons that remain obscure, a significant portion of heart failure patients who are candidates for proven therapies, including ACE inhibitors and beta blocking agents, are not receiving them.17,18 Even among those treated with these agents, dosing is often suboptimal or well below the doses proved efficacious in clinical trials. Second, patient compliance with prescribed medications and dietary and physical activity modifications is frequently poor. This partly reflects inadequate patient evaluation and follow-up as well as the confounding effects of psychosocial factors, such as depression, social isolation, and the inability to afford the high cost of multiple medications. Although many of these issues have been successfully addressed by various heart failure disease management strategies,19 access to such programs remains limited, largely because there is no established method of reimbursement for these services.

A third major element contributing to the relative lack of impact of new heart failure therapies is the fact that almost all of the major heart failure trials have targeted middle-aged patients with impaired left ventricular systolic function. Women, ethnic minorities, and elderly patients, who comprise most of the heart failure cases in the United States, have been markedly underrepresented in these trials. The applicability of the study findings to these major demographic subgroups remains uncertain.20 In fact, a recent meta-analysis of the ACE inhibitor trials failed to show a significant benefit of these drugs among 1,066 patients age 75 years or older.21 Furthermore, as Wells and Little point out, scant data are available to guide therapy in the 40% or more of patients (predominantly elderly women) with heart failure and preserved left ventricular systolic function, a condition associated with substantial disability.22

Conclusion

In discussing the future of heart failure, it is important to recognize that patients with symptomatic heart failure represent the proverbial tip

of the iceberg. There are millions

of Americans with what might

be termed “pre-heart failure,” or asymptomatic left ventricular systolic or diastolic dysfunction (stage B heart failure).16 There are even more who have prevalent risk factors, such as hypertension, diabetes, or obesity (stage A heart failure).16 For these patients, the importance

of preventive strategies, including optimal control of blood pressure, blood glucose, and serum lipid levels, and a healthy lifestyle, including exercise and weight control, cannot be overemphasized. Recent innovations notwithstanding, the prognosis for established heart failure remains dismal.