Evidence-based medicine and population-based care: caring for patients with heart failure.

Heart failure is not only common but—somewhat unique among cardiac conditions—its prevalence is increasing as the population ages and as modern cardiac care allows people with heart disease to survive longer. (I sometimes tell nurses and pharmacists that the prevalence of heart failure adds to their job security.) Despite tremendous advances in therapy, heart failure nonetheless brings with it a heavy burden of both mortality and morbidity. Half of affected patients die within five years after diagnosis, and severe symptoms and hospitalization are frequent. A fact not widely recognized is that nearly half of patients with heart failure have a normal ejection fraction.1 Clinical evidence regarding the management of these patients with preserved systolic function is relatively sparse. Fortunately for heart failure patients with a reduced ejection fraction (often called systolic heart failure), good evidence does exist regarding disease management. Controlled trials of tens of thousands of patients with systolic heart failure have identified three categories of medication that improve survival.2–4 These agents—now referred to as triple therapy—include beta-blockers, spironolactone, and vasodilators, such as angiotensin-converting enzyme (ACE) inhibitors. These medications reduce mortality, improve symptoms, and prevent hospitalization—favorable results that provide important impetus for developing clinical programs for management of heart failure. Within our heart failure program in the Kaiser Permanente Northern California Region (KPNC), the practice of evidence-based medicine must take into account the aspects of cardiac care about which existing clinical evidence is either imperfect or fails to address important issues. Use of implantable cardioverter defibrillators (ICDs) is one such topic. These devices represent a tremendous advance for patients with severely reduced ejection fraction: ICDs have reduced the risk of sudden death by as much as 90% in these patients, and earlier trials showed5–7 that high-risk patients treated with these devices derive a huge benefit from them—as much as a 14% to 20% reduction in absolute mortality over a two-year period. As these devices became smaller and safer to implant, trying them in lower-risk patients made sense; ideally, however, studies of this population should first screen out high-risk patients already known to benefit from the devices. Recently published studies (MADIT II8 and SCD-HeFT9) that included both high- and low-risk patients treated with ICDs showed a 4% to 7% absolute reduction in mortality over a two-year period. The question thus arises: If the high-risk patients had been removed from the analysis, would the residual benefit have been clinically significant? Would this benefit have been cost-effective? We do not know the answer with any certainty, but use of ICDs is nonetheless being expanded to lower risk patients on the basis of this imperfect evidence. An important topic lacking sufficient evidence is how to diagnose heart failure. An important topic lacking sufficient evidence is how to diagnose heart failure. No randomized trial has defined the best approach, and, unfortunately, no single sign, symptom, or test is pathognomonic. Because patients with heart failure can have a normal ejection fraction, normal results of echocardiography do not exclude the diagnosis; and neither does a reduced ejection fraction establish the diagnosis. Yet, because diagnosis is a crucial first step in caring for patients, a portion of our “evidence-based” guideline focuses on diagnosing heart failure despite the lack of sufficient evidence. Without programs to implement them, guidelines usually have little impact on clinical practice. Putting Evidence into Practice in the KP Northern California Region Synthesizing the evidence, “warts and all,” into the best possible clinical guideline is a necessary first step—but itself is insufficient—for disease management. Without programs to implement them, guidelines usually have little impact on clinical practice. For this reason, this article describes the KPNC Heart Failure Care Management Program, which is designed to ensure that our members with heart failure receive the best evidence-based care for this condition. Our program often hosts visitors from other US health plans—and even from other countries—who ask us: What is the secret of the program? Is it our disease management software? Is it our method of training care managers? Is it our medication protocols? Like Archimedes, these visitors seem to be seeking a lever long enough to move the world. But there is no single such lever. In our program, we have learned that we must pull multiple levers to influence clinical practice and that no single approach is equally effective for every clinician or in every clinical setting.