Longevity Calculator Could Aid Planning After Dementia Diagnosis

WEDNESDAY, Sept. 28, 2022 (HealthDay News) -- How long can someone newly diagnosed with dementia expect to live?

It’s a tough question but definitely one that many family members and friends grapple with after a loved one is diagnosed with dementia and begins to decline. Now, a new statistical model may help answer this question and aid in financial planning and decisions about medical care.

“This model provides estimates of an individual's risk of [dying] by having a clinician input various characteristics of their patient with dementia, such as age at diagnosis of dementia, body mass index, dependencies in activities of daily living, and [other diseases and conditions],” explained study author Dr. W. James Deardorff. He is a geriatrician at the University of California, San Francisco, and the San Francisco VA Health Care System.

The researchers also designed a companion risk calculator for people with dementia that's available online at ePrognosis.

According to the study, of nearly 4,300 people with probable dementia (average age 82) who didn’t live in a nursing home at the outset, 81% died during 10 years of follow-up. The new model predicted who would live and who would die in approximately 75% of cases. This model wasn’t designed to predict the short-term risk of dying.

Factors that most strongly predicted the risk of dying during the study included age, male sex, low weight (BMI below 18.5), former or current smoking status, chronic diseases, and difficulties walking several blocks and performing activities of daily living, such as grocery shopping. These findings were further validated in a separate group enrolled in the National Health and Aging Trends Study.

It’s not an easy conversation to have but it’s an important one, Deardorff said.

“A clinician can ask their patient and family whether they would like to hear this information, which may serve as a starting point for discussing overall treatment preferences,” he said.

This information on life expectancy can give families a head start on planning for the future. “It can help assist clinicians in talking with patients and families about medical decisions, such as whether to continue screening for cancer or how aggressive to treat chronic conditions like high blood pressure and diabetes,” he said.

For example, colon cancer screening with a colonoscopy may not be worth the discomfort and bleeding associated with the procedure in people who have a shorter life expectancy since these cancers tend to grow slowly. This information can also give people time to discuss whether they would want cardiopulmonary resuscitation (CPR) in the event of a cardiac arrest.

People who also have type 2 diabetes may want to reduce or stop insulin that they take to stave off vision loss and kidney failure down the road. These benefits may not be realized if their life expectancy is shortened, and the risks of low blood sugars from too much insulin can be serious, Deardorff said.

This information can also guide discussions about money as many people with dementia will need more help at home and may ultimately be admitted to nursing homes, he added.

These estimates are just one factor in decision-making for older adults with dementia and should be incorporated within the broader context of patient and family goals and preferences, Deardorff explained.

The study was published online Sept. 26 in JAMA Internal Medicine.

Dr. Catherine Sarkisian is a geriatrician and professor at the University of California, Los Angeles. She plans to use this tool when talking to patients with dementia and their families about what the future may hold.

“It is impossible to predict with certainty how long any person has to live, but this study used a national dataset to construct and test a prediction tool that can give ranges of the likelihood of being alive at different timepoints between one and 10 years,” she said.

“This has great potential to be very useful in combination with clinical judgment and doctor-patient communication skills,” said Sarkisian, who was not involved in the new study.

Family members of people with dementia with a shorter predicted life expectancy might decide to take a leave from work to be with their family member. “Alternatively, if the tool shows a longer life expectancy than the patient or family was expecting, this might be uplifting,” she said.

More information

The risk calculator for patients with dementia is available at the University of California, San Francisco.

SOURCES: W. James Deardorff, MD, geriatrician, University of California, San Francisco, and San Francisco VA Health Care System; Catherine Sarkisian, MD, geriatrician, professor, University of California, Los Angeles; JAMA Internal Medicine, Sept. 26, 2022, online