SAN FRANCISCO — Dementia is a leading cause of morbidity and mortality worldwide and is associated with increased mortality risk. An estimated 6.5 million Americans aged 65 years or older are living with Alzheimer’s disease and related dementias in 2022.
Dementia is a leading cause of mortality, with patients’ clinical course highly variable; median survival time from age at diagnosis ranges from 3.3 years to 11.7 years, according to a recent report in JAMA Internal Medicine.1
Better knowledge of prognosis has important implications for decisions related to financial planning, advance care planning, long-term care admission, and clinical care, according to researchers from the University of California, San Francisco, and the San Francisco VA Health Care System and colleagues. “For interventions that have immediate risks or burdens and delayed benefits, such as cancer screening and tight glycemic control in patients with diabetes, life expectancy can help differentiate between patients most likely to benefit vs most likely to be harmed by interventions,” they wrote. “Therefore, accurate estimates of life expectancy in people with dementia are important for providing the foundational data for patients, family, and clinicians to help define patient-centered care goals in their remaining lifetime.”
The study team’s goal was to develop and externally validate a mortality prediction model in community-dwelling older adults with dementia.
To do that, the investigators conducted a cohort study including community-dwelling participants (aged ≥65 years) in the Health and Retirement Study (HRS) from 1998 to 2016 (derivation cohort) and National Health and Aging Trends Study (NHATS) from 2011 to 2019 (validation cohort). Researchers from Ann Arbor, MI, VAMC also participated.
For the study, candidate predictors included demographics, behavioral/health factors, functional measures (eg, activities of daily living [ADL] and instrumental activities of daily living [IADL]), and chronic conditions. Defined as the primary outcome was time to all-cause death.
The mean age of 4,267 participants with probable dementia in HRS, was 82.2, with most, 69.4%, female, and 12.1% identified as Black. Median (IQR) follow-up time was 3.9 years, and 81.2% of participants died by the end of follow-up.
“The final model included age, sex, body mass index, smoking status, ADL dependency count, IADL difficulty count, difficulty walking several blocks, participation in vigorous physical activity, and chronic conditions (cancer, heart disease, diabetes, lung disease),” according to the authors. “The optimism-corrected iAUC after bootstrap internal validation was 0.76 (95% CI, 0.75-0.76) with time-specific AUC of 0.73 (95% CI, 0.70-0.75) at 1 year, 0.75 (95% CI, 0.73-0.77) at 5 years, and 0.84 (95% CI, 0.82-0.85) at 10 years. On external validation in NHATS (n = 2404), AUC was 0.73 (95% CI, 0.70-0.76) at 1 year and 0.74 (95% CI, 0.71-0.76) at 5 years. Calibration plots suggested good calibration across the range of predicted risk from 1 to 10 years.”
Researchers said they developed and externally validated a mortality prediction model in community-dwelling older adults with dementia “that showed good discrimination and calibration. The mortality risk estimates may help guide discussions regarding treatment decisions and advance care planning.”
- Deardorff WJ, Barnes DE, Jeon SY, Boscardin WJ, Langa KM, Covinsky KE, Mitchell SL, Whitlock EL, Smith AK, Lee SJ. Development and External Validation of a Mortality Prediction Model for Community-Dwelling Older Adults With Dementia. JAMA Intern Med. 2022 Sep 26:e224326. doi: 10.1001/jamainternmed.2022.4326. Epub ahead of print. PMID: 36156062; PMCID: PMC9513707.
