SUNDAY, March 10, 2002 (HealthDayNews) -- Clot-busting drugs, while extremely effective in younger people, may be dangerous and even deadly for the very elderly.
Massachusetts researchers have found that heart attack patients in their 80s and 90s are at least 40 percent more likely to die of strokes and other vessel-related problems after taking the drugs than if they didn't receive the therapy.
The findings are almost identical to a 2000 study by Johns Hopkins University researchers, who also observed that heart patients over age 75 were about 40 percent more likely to die within a month of being hospitalized if they were given clot-dissolving therapy.
"This is strongly suggestive of a problem. We believe that these drugs are more likely to cause bleeds and hemorrhagic strokes in older patients," said Stephen Soumerai, a Harvard University preventive care specialist and lead author of the latest study.
Clot-busting drugs, like streptokinase and tissue plasminogen activator (t-PA), a sort of molecular Drano, have become an integral, and highly effective, part of heart attack and stroke care. But Soumerai said the U.S. government has encouraged doctors
to use these drugs in the very elderly by making them part of the best-practice guidelines for Medicare, without knowing how well they work in the oldest age brackets.
"Many people generalize to the old-old without adequate data," said Soumerai, whose work appears in tomorrow's issue of the Archives of Internal Medicine.
He and his colleagues looked at medical records from 2,659 Minnesota heart attack patients treated at hospitals there between 1992 and 1996. Of those patients, 735, or about 28 percent, got clot-dissolving drugs.
Clot medications should be given within 12 hours of the onset of heart attack symptoms, and the choice to use them also depends on other factors, including a patient's electrocardiograph readings, blood pressure, and contraindications like a history of stroke or bleeding disorders.
Based on these criteria, 719 of the patients Soumerai studied were eligible for treatment with the drugs. Of those, 63 percent got them.
The researchers found that patients under age 80 were less likely to die in the hospital if they got the drugs than if they didn't. But those patients in their 80s and 90s who received the drugs were 40 percent more likely to die than those who didn't. The risk of death rose as much as 4 percent a year for every year over age 65.
Although older patients tend to be sicker and do worse after heart attacks, the study found that those who were given the clot drugs were generally healthier than people who didn't qualify to take them. "If patients are healthier coming in but are more likely to die, it's more of a concern," Soumerai said.
In addition, Soumerai said, the research showed that 27 percent of the people who received the drugs in fact had at least one risk factor that could have discouraged the treatment. For those patients, the risk of death was almost 60 percent higher than other patients with the risk factors who did not get the drugs.
"We need to set up protocols and systems to screen patients carefully, so that only those who are clearly eligible [for clot-busting drugs] receive them," Soumerai said.
But he added, even if very old heart attack patients meet the treatment criteria, "physicians should be cautious about giving these drugs."
Dr. Jerry Gurwitz, a professor of medicine at the University of Massachusetts Medical School in Worcester and a co-author of the latest study, said the findings of both studies should be a red flag to physicians.
They should avoid using clot-busting drugs in very elderly patients with any risks of serious side effects, such as a prior stroke or a bleeding condition, he said. "And when they do use them, they need to be dosed and monitored appropriately," he added.
"There certainly is concern," said Dr. David Thieman, a Johns Hopkins heart specialist who led the earlier research on clot-busting drugs and older patients. "But I don't think the question is ever going to be answered by observational studies."
What's needed, he said, are well-controlled trials designed specifically to address whether the drugs are indeed harmful to the very elderly.
What to Do: To learn more about stroke, visit the National Stroke Association or that American Heart Association.
