Patients are far more likely to survive a heart attack if they are admitted directly to a high-volume hospital rather than a smaller one, according to a study of nearly 100,000 patients by researchers at Johns Hopkins.
Results of the study, published in the May 27 issue of The New England Journal of Medicine, found that Medicare patients were 17 percent more likely to survive a heart attack if they initially were seen at a medical center that handles large numbers of such patients rather than a low-volume hospital, a difference of 2.3 lives per 100 patients.
The volume effect was particularly strong among younger patients, whose survival was more than 30 percent better at high-volume centers.
The overall experience of the hospital's medical team appeared to be the key advantage in the increased survival rate, says David R. Thiemann, M.D., lead author of the study and assistant professor of medicine at Hopkins. The presence of high technology equipment and specialists were less important. The use of clot-dissolving agents, other medications, bypass surgery and angioplasty accounted for about a third of the survival benefit.
"We estimate that more than 5,000 lives each year potentially could be saved by taking patients with heart attacks directly to high-volume hospitals," Thiemann says. "Until now, patients with chest pain typically have been taken by ambulance to the nearest hospital because transport time is important. Our study suggests that in urban and suburban areas, the hospital-volume effect may outweigh minor transport delays. Heart attack patients may benefit from a field triage system like that used for patients with major injuries, who are taken directly to specialized trauma centers.
"This does not mean," he cautioned, "that people should drive themselves across town for treatment rather than call an ambulance. But it does suggest that changes in the emergency medical system could dramatically improve survival for heart-attack patients."
For the study, researchers analyzed a Health Care Financing Administration database of 98,898 Medicare patients 65 years of age or older, who were treated for heart attack at all 4,055 acute care hospitals in the United States during 1994 and 1995.
Thirty days after hospital discharge, death rates were 14.4 percent at the highest-volume centers, compared to 16.7 percent at the lowest-volume centers. One year after the heart attack, death rates were 27 percent among those admitted to the highest-volume centers, compared to 29.8 percent at the lowest-volume centers.
The study also found that:
- Hospital technology did not matter as much as volume. After allowing
for volume, patients at hospitals that offer bypass surgery to re-route blood
around blocked arteries and angioplasty to open blockages did not do
significantly better than those at hospitals without these technologies.
- Patients treated by cardiologists had slightly better outcomes than
those treated by other physicians, but physician specialty did not affect the
overall association between hospital volume and survival. Altogether, 30
percent of patients had cardiologists as attending physicians, 37 percent had
internists and about 15 percent had family practitioners.
- Living in a less populated area was an independent risk factor for death after heart attack. Patients who lived in rural areas were 11 percent more likely to die than those in metropolitan areas.
The other study authors were Josef Coresh, M.D., Ph.D., and Neil R. Powe, M.D., M.P.H., M.B.A., of Hopkins; and William J. Oetgen, M.D., M.B.A., of the Delmarva Foundation for Medical Care.
Related Web sites: American Heart Association -- http://www.
Media Contact: Karen Infeld 410-955-1534