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EmailAugust 23, 2000
Recovering from a heart attack?
Study confirms beta-blockers in any dose save lives
But lower doses of the drug may offer additional benefit
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Toronto, ON - Baycrest Centre researcher Dr. Paula Rochon lead a study that finds heart attack survivors who are prescribed low dose beta-blockers may have a better chance of avoiding further heart failure compared to those on higher doses.
The findings are published in the August 19th, 2000 issue of the international medical journal The Lancet.
Conducted by Baycrest Centre for Geriatric Care and the Institute for Clinical Evaluative Sciences (ICES), the study looked at more than 13,000 Ontario seniors aged 66 and older who had suffered a heart attack between 1993 and 1995. Of that group, 8,232 had no previous history of heart failure and 4,681 of these were identified as receiving beta-blocker therapy after their heart attack.
The Baycrest-ICES study confirms what previous studies have found -- that beta-blockers save lives. In this study, seniors with no history of heart failure who were prescribed beta-blockers were 43% less likely to go back in hospital with heart failure (in one year of followup) compared to those not given the drug.
Looking more closely at those seniors on beta-blockers, researchers discovered that higher doses of the drug reduced the risk of going back in hospital with heart failure by 22%. Lower doses provided even greater benefit, reducing the risk of hospital re-admission with heart failure by 52%. This same dose-related risk persisted within the healthiest subgroup of 2,751 patients. Low dose was defined as lower than what is available in a standard tablet, and high dose as equal to or higher than the doses evaluated in clinical trials.
"We know that older and frailer patients often cannot tolerate higher doses of drugs, even though these dosages are often recommended in prescribing guidelines," says Dr. Paula Rochon, who led the Ontario study. "The problem is that the prescribing guidelines are based on clinical trials conducted on younger adults who may be more able to tolerate higher dosages."
Dr. Rochon strongly recommends that randomized clinical trials be held with older adults to identify the minimum effective dosage of beta-blockers. For now, doctors are advised to "start low and go slow" with dosages for older adults -- and many are already doing this, Dr. Rochon points out.
Dr. Rochon was assisted in this study by investigators that included Drs. Jack Tu, Geoffrey Anderson, C. David Naylor and John Paul Szalai (all of whom are affiliated with the University of Toronto's Faculty of Medicine), and Dr. Jerry Gurwitz of the Meyers Primary Care Institute in Massachusetts.
The Lancet study is the second of a two-part examination of this group of Ontario seniors. Last year, the same researchers published compelling results in the Canadian Medical Association Journal (Nov. 30th, 1999 issue) showing that almost half of Ontario seniors who suffered a heart attack between 1993 and 1995 were not prescribed beneficial beta-blocker drug treatment at all! While there may have been strong medical reasons for not giving the treatment to some older heart attack patients, many who were identified by the researchers as "ideal candidates" missed out.
Funding for both studies was provided by Physicians Services Incorporated Foundation.