Prevalence of Frailty Increases Throughout Adulthood

Laurie Barclay, MD

May 03, 2011

May 3, 2011 — The prevalence of frailty, which is linked to earlier death, increases throughout adulthood and not just after age 65 years, according to results from the Canadian National Population Health Survey reported online April 26 in the Canadian Medical Association Journal.

"The prevalence of frailty increases with age in older adults, but frailty is largely unreported for younger adults, where its associated risk is less clear," write Kenneth Rockwood, MD, from Dalhousie University and the Centre for Health Care of the Elderly in Halifax, Nova Scotia, and colleagues. "Furthermore, less is known about how frailty changes over time among younger adults. We estimated the prevalence and outcomes of frailty, in relation to accumulation of deficits, across the adult lifespan."

The study sample consisted of 14,713 community-dwelling respondents to the longitudinal component of the National Population Health Survey, with 7 two-year cycles beginning in 1994 to 1995. At baseline, age was 15 to 102 years, and 54.2% were women. Study endpoints were mortality, use of health services, and a Frailty Index constructed from 42 self-reported health variables measuring change in health status and accumulation of health deficits such as diseases, disabilities, symptoms, allergies, and other conditions. For more than 99% of the respondents, vital status was known.

With advancing age, the prevalence of frailty increased from 2.0% (95% confidence interval [CI], 1.7% - 2.4%) for participants younger than 30 years to 22.4% (95% CI, 19.0% - 25.8%) for those older than 65 years. For participants who were at least 85 years old, the prevalence of frailty was 43.7% (95% CI, 37.1% - 50.8%).

Compared with frail participants, relatively fit participants had lower 160-month mortality rate at all ages. At age 40 years, 160-month mortality rate was 2% vs 16%, respectively; and at age 75 years, it was 42% vs 83%, respectively. Participants who were initially relatively fit tended to remain relatively fit with time.

Compared with all other groups, the group with the most frailty had a greater proportion of participants using health services at baseline (28.3%; 95% CI, 21.5% - 35.5%) and at each follow-up cycle (26.7%; 95% CI, 15.4% - 28.0%).

"Deficits accumulated with age across the adult spectrum," the study authors write. "At all ages, a higher Frailty Index was associated with higher mortality and greater use of health care services. At younger ages, recovery to the relatively fittest state was common, but the chance of complete recovery declined with age."

Limitations of this study include fitness defined on the basis of self-reported data, missing data for at least 1 of the 7 cycles for nearly 25% of participants, and lack of data on social context.

"Our data suggest that it is not coincidence that use of hospital services increases in step with accumulation of deficits," the study authors conclude.

"Frailty, in all its complexity, challenges how we care for people. A particular challenge is to determine how insights about the complexity of frailty can be translated into a new approach to assessing and quantifying disease for patients who are frail, especially when they become acutely ill."

The Canadian Institutes of Health Research supported this study. Dr. Rockwood is seeking funding to develop a commercial version of the Frailty Index, and he will receive royalties from a publisher for work on a textbook about geriatric medicine. He is president of and owns stock options in Dementia Guide Inc, a company that tracks outcomes in clinical trials of dementia, and that has received contracts from Pfizer Canada, Medivation, GlaxoSmithKline, and Janssen Alzheimer Immunotherapy. The other study authors have disclosed no relevant financial relationships.

CMAJ. Published online April 26, 2011. Abstract

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