Published on: May 22, 2014
by Donna Zulman & Keith Humphreys for The New York Times:
When older patients seek health care, they are unwittingly enrolling in an experiment: Will medical procedures that have been proved effective mainly on the young also help the elderly?
Doctors are often in the dark about whether certain drugs, procedures and tests will benefit older adults, because these patients are routinely excluded from medical research. A systematic review in The Journal of the American Medical Association in 2007 looked at randomized controlled trials published in high-impact medical journals between 1994 and 2006, and found that close to 40 percent excluded individuals over the age of 65. Clinicians consequently have to extrapolate findings about diseases as diverse as cancer, heart attacks and mental illness from studies of younger and often healthier people, potentially putting their older patients at risk.
A patient’s age affects all sorts of treatment decisions. For example, as people get older, they generally experience a decline in kidney and liver function, which can affect the way their bodies process medications. This can lead to increased drug levels in the body, resulting in more side effects like dizziness, drowsiness and depression. As a result, older people often need to take smaller doses than studies of younger adults suggest.
Another important example involves diabetes. Early diabetes studies conducted mainly with younger patients suggested that maintaining low blood sugar levels might decrease the risk of heart attack and stroke. But when researchers studied a population that included older adults and patients with longstanding diabetes, they found that intensive blood sugar treatment did not have this benefit, and actually increased the risk of dangerous outcomes, including hypoglycemia. Many clinicians are now recommending less stringent blood sugar goals for their older diabetic patients.
Researchers often impose age limits in clinical trials because they are concerned that elderly patients will have complicated health issues that pose practical or ethical challenges to their participation. However, advanced age is not a reliable proxy for poor health. If researchers are worried that studying people with certain health conditions will increase the risk of side effects or complicate the interpretation of the results, then they should exclude participants based on those health conditions — not on their age alone.
Today, around 13 percent of Americans are 65 or older, and this proportion is expected to grow to more than 20 percent by 2030. The Agency for Healthcare Research and Quality reports that older adults — who tend to have more chronic medical conditions and a greater risk for functional and cognitive decline — accounted for more than $333 billion in health care expenses in 2006. As clinicians who care for older patients ourselves, we want to make sure that we’re giving them the best treatment possible. But we can’t do that if we don’t have evidence for what works and what doesn’t.
Older people aren’t the only ones who have been underrepresented in medical research. The National Institutes of Health started requiring studies to include women only in 1993. Last week, it called for researchers to start testing new drugs and treatments on more female lab animals. This is a welcome trend. Ending the exclusion of older patients should be the next step. (It would also have a major impact on female patients, because the majority of older adults are women.)
The N.I.H. and other public funding agencies should prohibit the exclusion of study subjects solely on the basis of age, just as they prohibit the exclusion of women and minorities. And the Food and Drug Administration should require that new drugs and medical devices be tested on older adults before approval, when appropriate. Finally, medical journals and reviewers should insist that researchers who left out older participants explain why they did so, and include a discussion about what that might mean for the results.
Addressing the underrepresentation of older adults in medical research won’t be easy; researchers will have to work to ensure that recruited patients reflect the spectrum of health issues common among older individuals, and many older patients will have to volunteer to participate in clinical trials. But continuing the current exclusionary practices will only create more scientific evidence that cannot be generalized to a growing, complex and costly cohort of aging patients.
Medical researchers have become increasingly committed over the past half-century to allowing all citizens to participate in studies, in order to benefit all citizens. Older Americans are our patients, too. We can’t leave them out.
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