Chronic disability in older Americans greatly overestimated

The rates of chronic disability in older Americans has been substantially overestimated by about forty percent, researchers at Yale School of Medicine report in the December 12 Archives of Internal Medicine.

"Our projections yielded about two million fewer chronically disabled older Americans in 1999, relative to the published estimate of seven million," said Thomas M. Gill, M.D., who co-authored the study with Evelyne A. Gahbauer, M.D.

Gill, associate professor of medicine/geriatrics, obtained his findings using data from the "Yale PEP Study," which seeks to better understand how older persons manage day-to-day activities and remain independent at home. Titled "Epidemiology of Disability and Recovery in Older Persons," the PEP study includes 754 participants age 70 or older from the Greater New Haven area. Over the last eight years, participants have shared their experiences during a series of home assessments and monthly telephone interviews focusing on essential activities of daily living, such as bathing, dressing and walking.

Patients were classified as having chronic disability based on the presence of disability during consecutive monthly interviews immediately before or after the fourth comprehensive assessment. Of the 552 participants, 16.1 to 17.2 percent met criteria for chronic disability, leading to a national estimate ranging from 4.9 to 5.3 million chronically disabled older Americans.

Gill said accurate estimates of chronic disability are important for a variety of reasons. From a policy perspective, these estimates are often used to inform decisions regarding the current and future health care needs of older persons and to forecast the likely demand for long-term care. From an epidemiologic perspective, the causes of chronic disability, including pre-disposing risk factors and subsequent precipitants, may differ from those of short-term disability.

"From a personal perspective, the likelihood of recovery is considerably lower for chronic disability than for short-term disability; and chronic disability likely confers a higher risk of subsequent morbidity and mortality," said Gill. "Given the dynamic nature of disability, new strategies are needed to adequately capture the true burden of chronic disability among elderly persons."