All physicians in this study tended to prescribe ACE inhibitors to patients with symptomatic heart failure already receiving digitalis and a diuretic, but family practitioners and general internists tended to underutilize these medications in other subsets of patients with reduced ejection fractions, including the asymptomatic patient, the asymptomatic patient who is post–myocardial infarction, and the newly symptomatic patient with heart failure. Differences across specialties were most striking among asymptomatic and post–myocardial infarction patients.
What could explain the differences in the use of ACE inhibitors across specialties, particularly among asymptomatic patients? Even after adjusting for the number of patients with heart failure that each physician treats, the estimated relative risk reduction from using medications in each case simulation, and the estimated rates of side effects from ACE inhibitors, cardiologists were still more likely to use these agents.
Nonetheless, we cannot rule out a number of other potential causes. For example, different physicians may require different amounts of scientific evidence to modify their practice. Generalist physicians may be aware of the latest studies, but might be withholding judgment pending more data. Or, differences between the types of patients with heart failure cared for by generalists and cardiologists may explain part of the variation in the pattern of drug selection. Perhaps patients cared for by generalist physicians are less likely to afford ACE inhibitors.
We suspect, however, that ineffective dissemination of information about the specific role of ACE inhibitors in patients with asymptomatic heart failure is probably also playing a role.18
Compared with cardiologists, generalist physicians found original research articles less helpful and their colleagues’ advice more useful.
Our data also suggest underdosing of ACE inhibitors. In the various clinical trials, the doses of the ACE inhibitors were generally increased to a target dose whenever tolerated. Trials currently in progress are testing the efficacy of lower doses.19
Until these results are reported, an evidence-based approach to medicine advocates using the higher dosages that have already been proved to reduce mortality and morbidity.9
In addition, the major practice guidelines and some heart failure experts argue that many physicians have been too cautious in using ACE inhibitors, particularly among patients with relative hypotension or renal insufficiency.8,9,19
Patients with asymptomatic hypotension or moderate renal insufficiency might benefit from the adequate dosage of these medications.20,21
Our study has several limitations. The major limitation is that it is a simulation-based survey that does not examine actual physician behavior.22
We measured knowledge and attitudes about medication use. However, given this hypothetical “test” situation in which the social desirability bias would be to increase the number of “correct” answers, we are probably overestimating the use of ACE inhibitors compared with actual clinical practice. Nonetheless, there is no reason to expect any differential bias across specialties.
Our study has several strengths. We used a national sample of physicians. Our response rate is comparable or higher than that of other physician surveys of prescribing behavior.,23–25
In addition, we used a level of clinical detail in the case simulations that would be extremely difficult to replicate with other methodologies on a national level, allowing us to describe prescribing behavior for patients with heart failure across a range of illness severity.
Several different types of interventions may improve physicians’ use of ACE inhibitors in patients with heart failure. First, intensive educational efforts,26
and carefully designed incentives to increase the practice of evidence-based medicine 28,29
may improve the use of these medications. However, it is extremely difficult to alter physicians’ practice styles.30
Second, early specialty consultation might be encouraged. Knowledge increases rapidly, and tends to be adopted first by specialists. Nonetheless, we cannot extrapolate from our data that continuing care from a specialist, especially among the least sick patients, will necessarily lead to better outcomes.
Third, coordinated multidisciplinary interventions and disease management programs for heart failure, of which medication guidelines are an integral part, could improve the appropriateness of drug selection and decrease hospital readmissions and costs.31,32
These programs’ effects on noncardiac outcomes also need to be analyzed, particularly as so many older patients have multiple comorbid conditions.1
The best solution for one health care system may not be generalizable to other organizations. Therefore, it may be prudent to allow each health care delivery system to devise the specific manner in which the care of its patients with heart failure is coordinated among different health care providers. Because congestive heart failure is the most common cause of hospitalization in the Medicare population,33
flexible practice arrangements with easy access to specialists may reduce costs as well as improve outcomes.