A number to guide your health decisions (it’s not your age)
During her annual visit, the patient’s doctor asks if she would like to continue having regular mammograms for breast cancer screening, then reminds her that it has been almost ten years since her last colonoscopy.
She’s 76. Hmmm.
The age of the patient alone can be an argument against further mammography appointments. The independent and influential US Preventive Services Task Force recommends mammography screening for women ages 40 to 74 in its latest draft guidelines, but says, “Current evidence is insufficient to assess the balance between the benefits and harms of mammography screening in women ages 75 and older.”
Colorectal cancer screening with a colonoscopy or a less invasive test also becomes questionable as people get older. The task force gives a grade of C for those aged 76 to 85, meaning “at least moderate certainty that the net benefit will be small.” It should only be offered selectively, according to the guidelines.
But what else is true about this hypothetical woman? Does she play tennis twice a week? Does she have a heart condition? Did your parents live well into their 90s? does she smoke
Some or all of these factors affect their life expectancy, which in turn can make future cancer screening tests either useful, pointless, or even harmful. The same considerations apply to a range of health decisions as we age, including those involving medication, surgery, other treatments, and screening.
“There’s no point in drawing those boundaries by age,” said Dr. Steven Woloshin, internist and director of the Center for Medicine and Media at the Dartmouth Institute. “It’s age and other factors that limit your life.”
As a result, some medical associations and health advocacy groups have slowly begun to change their approaches, basing recommendations for testing and treatment on life expectancy rather than just age.
“Life expectancy gives us more information than age alone,” said Dr. Sei Lee, geriatrician at the University of California, San Francisco. “It more often leads to better decision-making.”
Some recent Task Force recommendations already reflect this broader perspective. For older people undergoing lung cancer testing, for example, the guidelines recommend considering factors such as smoking history and “a health condition that significantly limits life expectancy” when deciding when to stop screening.
The Colorectal Screening Task Force guidelines call for consideration of an elderly patient’s “health status (e.g., life expectancy, comorbidities), prior screening status, and individual preferences.”
The American College of Physicians also includes life expectancy in its guidelines for prostate cancer screening; This also applies to the American Cancer Society in its guidelines for breast cancer screening for women over 55.
But how does this 76-year-old woman know how long she will live? How does anyone know?
A 75-year-old has an average life expectancy of 12 years. But when Dr. Eric Widera, a geriatrician at the University of California, San Francisco, analyzed census data from 2019 and found huge differences.
The data shows that the least healthy 75-year-olds, the bottom 10 percent, are likely to die in about three years. The top 10 percent would probably live another 20 years or so.
All of these predictions are based on average values and cannot accurately determine the life expectancy of any individual. But just as doctors constantly use risk calculators to decide, for example, whether to prescribe medication to prevent osteoporosis or heart disease, consumers can use online tools to get approximate estimates.
For example, Dr. Voloshin and his late wife and research partner, Dr. Lisa Schwartz, of the National Cancer Institute in developing the Know Your Chances calculator, which went live in 2015. First, he used age, sex, and race (but only two, black or white, due to limited data) to predict the probability of dying from certain common diseases and the overall probability of dying over a five to 20-year period.
The institute recently revised the calculator to add smoking status, a critical factor in life expectancy over which users have some control, unlike the other criteria.
“Personal decisions are driven by priorities and fears, but objective information can help guide those decisions,” said Dr. Barnett Kramer, an oncologist who headed the institute’s cancer prevention unit when it released the calculator.
He called it “an antidote to some of the anxiety-provoking campaigns patients see on TV all the time,” courtesy of drugmakers, medical organizations, advocacy groups, and alarming media reports. “The more information they can glean from these charts, the better they can guard against making health care decisions that don’t help them,” said Dr. Chandler. He pointed out that unnecessary testing can lead to overdiagnosis and overtreatment.
A number of health care institutions and groups offer online calculators specific to the disease. The American College of Cardiology offers a “risk estimator” for cardiovascular disease. A calculator from the National Cancer Institute assesses breast cancer risk, and Memorial Sloan Kettering Cancer Center provides a calculator for lung cancer.
However, calculators looking at individual diseases do not typically compare risks to mortality from other causes. “They don’t give you context,” said Dr. Voloshin.
Probably the most comprehensive online tool for estimating life expectancy for older adults is ePrognosis, created in 2011 by Dr. Widera, Dr. Lee and several other geriatricians and researchers. Intended for use by healthcare professionals, but also available to consumers, it provides about two dozen validated geriatric scales for estimating mortality and disability.
The calculators, some for patients living alone and others for patients in nursing homes or hospitals, contain extensive information on medical history and current functioning. It is helpful that there is a “Time to Benefit” tool that illustrates which tests and interventions may still be useful at certain life expectancies.
Consider our hypothetical 76-year-old. If she is a healthy non-smoker, has no trouble with her daily activities, and can easily walk a quarter mile, among other things, a mortality scale from ePrognosis shows that her longer life expectancy makes mammography a reasonable choice, regardless of age guidelines.
“The risk of just using age as a cut-off means we sometimes undertreat very healthy seniors,” said Dr. cons.
On the other hand, if she is a former smoker with lung disease, diabetes, and limited mobility, the calculator indicates that she should probably continue taking a statin, but may drop out of breast cancer screening.
“Competing mortality” — the possibility that another disease will cause her death before the one being screened for — means she is unlikely to live long enough to benefit from it.
Of course, patients will continue to make their own decisions. Life expectancy is a guide and not a limit for medical care. Some older people never want to stop exams, even when the data shows they are no longer helpful.
And some are not at all interested in discussing their life expectancy; This also applies to some of their doctors. Each party may overestimate or underestimate risks and benefits.
“Patients simply say, ‘I had a great-uncle who lived to be 103,'” recalls Dr. Chandler. “Or if you tell someone, ‘Your chances of long-term survival are one in 1,000,’ a strong psychological mechanism causes people to say, ‘Oh thank God, I thought it was hopeless.’ I’ve seen it all along.”
But for those who want to make health decisions based on evidence-based calculations, the online tools provide valuable context that goes beyond age. When you consider projected life expectancy, “rather than being scared of what’s in the news that day, you’ll know what to focus on,” said Dr. Voloshin. “It anchors you.”
However, the developers want patients to discuss these predictions with their doctors and warn against making decisions without their participation.
“This is meant to be a starting point for discussions,” said Dr. Voloshin. “It’s possible to make much more informed decisions — but you need some help.”