DURHAM, N.C. -- Elderly patients treated in a hospital for a heart attack were 12 percent less likely to die from the ailment if their doctor was a cardiologist rather than a primary care physician, a Duke University Medical Center study has shown.
The researchers say the findings have wide implications in view of the current strategies of managed care to limit access to specialists. "Up to now, most efforts to reform expensive traditional medicine have focused on containing cost by increasing use of primary care physicians. This study indicates we also need to pay close attention to patient outcomes," said the primary author, cardiologist Dr. James Jollis.
The study, published in the Dec. 19 issue of the New England Journal of Medicine, is the first reported that assesses whether the type of physician treating acute heart attack patients makes a difference in outcomes. Heart attack is the single largest killer of Americans. Annually, about 1.5 million people suffer a heart attack, about 750,000 are hospitalized, and one-third of them die, according to the American Heart Association.
The study was funded by the federal Agency for Health Care Policy and Research and conducted at the Duke Clinical Research Institute. Working with Jollis were Duke cardiologists Drs. Daniel Mark, Robert Califf, Donald Fortin, and Eric Peterson, and Duke statisticians Elizabeth DeLong and Lawrence Mohlbaier.
The researchers studied all 220,535 Medicare patients who suffered a heart attack in 1992 and found that the 64 percent of the patients admitted to a hospital and attended by primary care physicians had a lower chance of survival than the 34 percent of patients under the care of cardiologists. They say the results could not be explained by hospital or patient characteristics.
"It stands to reason that a doctor who focuses on hearts would likely provide a different level of care than those who treat a wide variety of diseases, and this study bears out that assumption," Jollis said. "Cardiologists are trained to recognize and treat heart attacks and to manage complications."
"It's not that cardiologists are better doctors than primary care physicians. Rather, the study validates the saying that 'practice makes perfect,'" said co-author Mark, a cardiologist and director of the Outcomes Research and Assessment Group at Duke. "Doctors with a lot of experience caring for a particular disorder do a better job on average than physicians who treat that disease infrequently, especially in high risk patients. The same notion exists within cardiology, too. We've found that physicians need to do many by-pass surgeries and angioplasties to have the highest quality results."
Primary care physicians include internists, who treat only adults, and family care practitioners. Some managed care plans concentrate care with primary care physicians as much as possible, and in many traditional fee-for-services medical plans, primary care physicians can admit patients to hospitals and be their patient's attending doctor.
The authors say the study flags several major issues that should be addressed in the U.S. health care system. "Although the results of the study alone cannot be used to justify a policy requiring all patients with acute heart attacks to be cared for by a cardiologist, our findings indicate a critical need to define better the differences between specialty and primary care and the effects of those differences on outcomes," Jollis said.
Additionally, researchers and physicians need to determine the point at which heart disease is severe enough that patients would benefit from seeing a cardiologist. "Severely ill patients in this study represented one end of the spectrum of disease, and we recognize that there is some level of illness below which primary care would be similar, if not superior to, specialty care, such as treatment of high blood pressure by a physician who knows a patient's complete medical history," said Jollis. "We need further study to determine where specialty care begins to make a difference, and so is worth the added expense."
Indeed, the study did find that along with saving more lives, cardiologists cost the health care system more than primary care physicians. Patients admitted by cardiologists underwent more diagnostic and therapeutic procedures, had longer hospital stays, and received more medication to control their heart disease than patients treated by other physicians.
"In fact, the study identified one of the mechanisms that may have led to improved survival," Jollis said. "Patients treated by cardiologists were more likely to receive survival-prolonging medications, including thrombolytic therapy, beta blockers, and aspirin.
"This suggests that one strategy to improve care among patients by primary care physicians would be to increase the use of those medications through guidelines and training," Jollis said. "In addition, other beneficial approaches may include the use of cardiology consultations and the transfer of patients to specialty services in certain situations."
Study researchers first examined the records of all Medicare patients who had a heart attack in the U.S. in 1992. The mean age of the patients was 76 and they were split evenly between men and women.
The researchers looked to see what happened to the 220,535 patients one year after they were hospitalized for a heart attack, and they found that 38 percent of the patients seen by primary care physicians had died, compared to 30 percent who had seen a cardiologist.
Then the researchers examined the medical records on a subset of these Medicare patients for which detailed clinical and outcome information was available. They looked at the outcome of 8,241 patients in four states, Alabama, Connecticut, Iowa, and Wisconsin.
In examining this group, the researchers statistically adjusted for disease severity and other factors, such as hospital type, to arrive at an accurate comparison of the treatment given to patients per type of physician -- an analysis not possible for the larger group of patients because comparison information was limited in their records. In the small group, for example, researchers found out that patients referred to care by cardiologists tended to be several years younger and male, according to Jollis, and they statistically adjusted this "bias" in the analysis, he said. After adjusting for these differences in patient and hospital characteristics, the researchers found that patients treated by cardiologists had a 12 percent lower risk of death at one year.
Among other results, the researchers found that:
- Cardiologists ordered a diagnostic catheterization on their patients 49 percent of the time, compared to 25 percent ordered by primary care physicians. Overall, cardiologists identified more patients with severe coronary disease with catheterization who would benefit from angioplasty or by-pass surgery.
- Cardiologists referred 22 percent of their patients on to an angioplasty procedure or by-pass surgery compared to 9 percent by primary care physicians.
- Cardiologists were more likely than generalists to use survival-prolonging medications in their treatment of heart attack patients. For example, 52 percent of patients cared for by cardiologists received beta blockers to reduce heart stress compared to 38 percent by the generalists.
- Patients at rural hospitals were much more likely to be seen by a generalist (89 percent) than a specialist (11 percent).