Studies Find Doctors Still Not Using Some Proven Drugs

Two different analyses by Duke University Medical Center cardiologists have shown that while multi-center clinical trials involving thousands of patients have clearly demonstrated that certain drugs can improve the outcomes for heart patients and save lives, the message is not being uniformly heard by physicians. During the past decade, large-scale randomized clinical trials have shown the effectiveness of such agents as beta blockers, ACE inhibitors and aspirin in reducing the number of deaths due to heart disease. While one might assume that the results of these trials would change the way physicians practice, that is not always the case, the researchers say. The Duke studies show, for example, that the acceptance rates by doctors of different classes of new drugs varies widely, and can vary from region to region across North America. A preliminary analysis by the Duke researchers determined that if every patient who was an appropriate candidate for one of the proven therapies actually received the therapy, more than 80,000 lives a year could be saved. The results of the two Duke analyses were prepared for presentation during the 50th annual scientific sessions of the American College of Cardiology. Best Candidates Receive Least After analyzing one of the most comprehensive and representative registries of heart patients in the world, Duke University researchers found that of five therapies proven effective by clinical trials, the usage ranged from 57 percent for ACE inhibitors to 93 percent for aspirin. The researchers studied the care received by nearly 10,000 patients enrolled at 94 hospitals in 14 countries who are part of the Global Registry of Acute Coronary Syndromes (GRACE) to see how often the findings of new clinical trials are really being put into practice. For each of the five therapies, they looked at how many patients who were candidates for the therapy actually received it. "There was a broad range in the usage of the therapies, which shows that while we've had some success in convincing physicians to use them, there still exists a great opportunity for improvement," said lead researcher Dr. Christopher Granger. "It is obvious that many people who could benefit from these newest therapies still aren't getting them." Specifically, the researchers found the following usage for the five therapies for patients with severe coronary syndromes:

Aspirin: 93 percent received aspirin while in the hospital, and 89 percent were prescribed aspirin after discharge. Aspirin, which can keep platelets from "clumping" together and forming clots, has been a mainstay of heart care for many years. Beta blockers: 81 percent received beta blockers in the hospital, 71 percent at discharge. This class of drugs protects the heart by keeping it from overreacting to stress hormones. ACE inhibitors: 64 percent received this drug in the hospital, 57 percent at discharge. ACE inhibitors dilate blood vessels and act similarly to beta blockers. Reperfusion therapy: Seventy percent of patients who could have received angioplasty or thrombolytic therapy (so-called clotbusting agents) actually received the therapy. Low-molecular weight heparin or intravenous GP IIb/IIIa inhibitors: Only 58 percent of patients who could have benefited from this newest class of drugs actually received the therapy. These drugs work similarly to aspirin by preventing blood from clotting.

"Certain drugs, such as aspirin, have higher use, perhaps related to public awareness of their benefits," Granger said. "The other surprising and paradoxical finding is that those patients who are at the highest risk -- and therefore those who have the most to gain -- are less likely to receive proven therapies." Also, the researchers found that in the case of aspirin, beta blockers and ACE inhibitors, patients were much more likely to receive proven therapy if their doctor was a cardiologist, Granger said. For these reasons, Granger advocates developing a system whereby doctors and patients would have to consult a checklist before hospitalization or at discharge to ensure that the latest therapies were considered for that particular patient. Electronic systems for guiding and tracking, which have been used less in medicine than other industries for quality assurance, have been shown to improve use of effective therapies, he said. The analysis was supported by the Duke Clinical Research Institute. Drug Prescription Varies Regionally While the use of different therapies to treat or prevent heart attacks varies widely across the United States and Canada, Duke researchers found that regions with the highest use of percutaneous coronary interventions had the lowest rates of evidence-based medications. The Duke researchers wanted to see how the different regions of the country used the following proven therapies -- aspirin, beta blockers, ACE inhibitors and percutaneous coronary interventions, such as angiography and angioplasty -- for improving survival of heart patients. Unlike the other therapies, aspirin was used uniformly in more than 95 percent of the patients across the regions. The researchers, led by DCRI cardiology fellow Dr. M. Cecilia Bahit, studied the data collected during ASSENT II, an international trial that enrolled 16,949 heart attack patients between October 1997 and November 1998. Of that group of patients, 4,806 (28 percent) were treated in the U.S. and Canada. "In the ASSENT II trial, 87 percent of the 'eligible' patients who would benefit from beta blockers actually received the drug," Bahit said. "That is up from 72 percent from another large trial (GUSTO-I) in the early 1990s, but it stills shows we have room for improvement." Some of the regional characteristics include:

• The West-Central United States had the highest rate of percutaneous interventions (53 percent) while New England had the lowest rate (36 percent).
• The Mid-Atlantic region and New England used beta blockers 92 percent of the time, while the West-Central region had the lowest (82 percent).
• ACE inhibitors were least used in the East-Central U.S. (42 percent) and most used in the Mid-Atlantic region (51 percent).
• Canada, which has a different health care system than the U.S., used percutaneous coronary interventions far less frequently (13 percent) and had higher use rates of beta blockers (85 percent) and ACE inhibitors (52 percent).

"This is a snapshot of how these therapies are used in North America," Bahit said. "We do not know why there is a such a disparity between regions of the U.S., especially since the health care system is much the same. If we could better understand these regional differences, we could be able to improve the care for our patients. "The bottom line is that while we are getting better, we can still save many more lives if more doctors put into practice what we learn from these clinical trials," she said. The analysis was supported by the Duke Clinical Research Institute.