Heart failure results when the heart muscle cannot efficiently pump blood through the body. Fluids back up in the lungs or other parts of the body -- causing a vicious cycle in which pressures within the heart rise and the already weakened organ undergoes further damage by trying to pump against this increased pressure. The condition can result from a heart attack, damaged heart valves, high blood pressure, lung disease, infection or several other causes. In many cases, it can be treated or even reversed by appropriate therapeutic interventions. The American Heart Association estimates that 4.7 million Americans are affected by heart failure, the single most frequent cause of hospitalization for those 65 and older, and 250,000 die each year.
ACE inhibitors act both by relaxing the arteries, which lowers blood pressure and makes the heart's job easier, and by adjusting levels of hormones that control blood pressure and heart function. The first ACE inhibitor, captopril, was introduced in the 1970s to treat high blood pressure, and numerous studies during the 1980s and 1990s strongly indicated that these drugs reduced death and disability in patients with heart failure. In recent years, both the American College of Cardiology and the U.S. Agency for Health Care Policy and Research have issued clinical guidelines recommending ACE inhibitors to treat heart failure. In general, the guidelines suggest that ACE inhibitors be tried in a broad range of patients with mild to severe heart failure before other types of medication, such as digoxin and diuretics. Stafford's team found that more than twice as many heart failure patients were taking diuretics in 1994 as were taking ACE inhibitors.
The MGH team reviewed information from the 1989 through 1994 National Ambulatory Medical Care Surveys. More than 9,500 physicians from many specialties and geographic areas reported on the services they provided during all patient visits during a randomly selected week. The researchers found that prescriptions for ACE inhibitors increased from 24 percent of heart failure visits in 1989 to 31 percent in 1994, an increase that was much lower than expected with the growing evidence of the medications' effectiveness. They also found that ACE inhibitor prescriptions were more likely in visits to cardiologists, in the Midwest, for white patients, for privately insured patients and for male patients.
"Although we don't have a specific percentage of heart failure patients that should be receiving ACE inhibitors, I'd estimate it's probably between 50 and 75 percent, much more than we found in this study," Stafford says. "We're not sure why they're being so seriously underprescibed. It could be a combination of lack of knowledge, an unrealistic assessment of their negative side effects -- of which there are very few -- and a lack of attention to preventive measures," he adds.
Stafford notes that there could have been an increase in ACE inhibitor usage in the three years after those examined in this study, but that additional efforts to educate both physicians and patients about their usefulness are probably needed. The variations seen in the use of ACE inhibitors by physician specialty, race and geographic region suggest that the recommended practices are not being uniformly applied, he says.
Stafford's coauthors are Demet Saglam, MA, and David Blumenthal, MD, MPP, director of the MGH Health Policy Research and Development Unit. Information in this study was originally presented last fall at the 1996 American Heart Association meeting. The study was supported by grants from the Agency for Health Care Policy and Research and the National Heart, Lung and Blood Institute.
Journal
Archives of Internal Medicine