A significant percentage of U.S. women 70 years or older who were severely cognitively impaired received screening mammography that was unlikely to benefit them, according to a study of 2,131 elderly women conducted by researchers from the University of California, San Francisco.
Overall, 18 percent of severely cognitively impaired women in the study received screening mammography, compared with 45 percent of women with normal cognitive status. However, severely cognitively impaired women who were married and had a net worth of more than $100,000 had a screening rate of 47 percent.
"Screening" mammography is imaging conducted to detect masses that are not causing any symptoms but may grow to cause symptoms in the future. It is distinguished from mammography conducted after a suspicious mass has been detected on physical exam.
"Even a screening rate of 18 percent may be considered too high,'' says lead author Kala Mehta, DSc, MPH, a geriatrics researcher at UCSF. In order to benefit from screening mammography, she explains, "a woman must have a life expectancy of at least four to five years,'' whereas the severely cognitively impaired women in this study had a life expectancy of 3.3 years on average. "Otherwise,'' she says, "the potential harms are likely to outweigh the benefits.''
Those harms, according to Mehta, include invasive follow-up tests such as biopsies in women who may not even understand why they are getting the tests; complications from those tests; surgery for asymptomatic growths that would never have caused problems in the woman's lifetime; and diverting time and focus away from medical care that enhances day-to-day quality of life for persons with dementia.
The women in the study were part of the 2002 wave of the Health and Retirement Study, an ongoing national prospective study sponsored by the National Institute on Aging that is examining the relationship between health, income, and wealth over time. Screening mammography rates were based on Medicare claims.
Based on their study, which appears on January 14, 2010 in the online "First Look" section of the American Journal of Public Health, the authors estimate that approximately 120,000 screening mammograms were performed on severely cognitively impaired women in the United States in 2002.
The study authors call for screening mammography guidelines that explicitly recommend against screening severely cognitively impaired older women.
"I don't think most people would say that putting a very demented older woman through screening mammography is a good thing," says principal investigator Louise C. Walter, MD, an associate professor of medicine at UCSF.
"Screening an active, healthy, independent 75 year old woman who is likely to live for another 15 or 20 years is one thing, but severely cognitively impaired older women with limited life expectancies have immediate health challenges that must take priority."
Mehta emphasizes that she and Walter do not advocate a strict cut-off age for screening. "Health status and life expectancy vary a lot among older people, so screening guidelines for older people should take into account health conditions that increase the risk for harm from screening, instead of focusing solely on age," she says.
"For each older woman, screening mammography should be an individual decision based on informed discussion with her physician. Our data can help physicians and caregivers make sure that elderly cognitively impaired women are getting the best care possible."
Co-authors of the study are Kathy Fung, MS, and Christine Kistler, MD, and Anna Chang, MD, of UCSF.
The study was supported by funds from the National Institute on Aging. Dr. Walter is a Robert Wood Johnson Physician Faculty Scholar at UCSF.
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