Published in UAB Insight, Winter 2008
ABSTRACT: Declines in mobility often go undetected and reflect decreases in health associated with increased mortality.
CME OBJECTIVE: The reader will understand the concept of life-space mobility and learn to assess life-space and identify modifiable risk factors for its decline.
Richard M. Allman, MD, grants and research support National Institute on Aging
The US population older than 65 years will more than double in the next 2 decades, rising from 35 million in 2003 to 72 million by 2030. This aging population, which is set to live longer than any previous generation, will need a radically redesigned health care system to ensure their elder years are as healthy and productive as possible, says gerontologist Richard M. Allman, MD, director of UAB’s Center for Aging, Division of Gerontology, Geriatrics, and Palliative Care, and the Birmingham/Atlanta VA Geriatric Research, Education, and Clinical Center.
“This is the first time in our world’s history that we have seen such a seismic shift in the population, which is changing rapidly from a triangle, with lots of young people at the base and a very few older individuals at the top, to a rectangle with almost equal numbers of young and old,” he says.
In 1900 just 1 in 25 Americans was older than 65 years. Today 1 in 8 is 65 years or older, and by 2050, the elderly will account for 1 of every 5 Americans.
“Our current health care system is based on an acute care model, designed largely to care for younger, basically healthy people who receive treatment, get better, and then return to their lives. It was not set up to handle the complex needs of older individuals with multiple chronic illnesses,” says Allman, who notes that much preventable morbidity and mortality experienced by older persons arises from this disconnect.
The causes of problems are myriad: adverse reactions to polypharmacy; hospital-associated morbidity; inadequate pre- and posthospitalization planning; a lack of affordable home care; limited preventive care; outdated nursing home models; and limited integration among primary care physicians, hospitals, and community-based programs.
Individual physicians cannot solve the considerable systemic problems of modern health care. They can, however, take simpler steps to optimize care for their older patients by identifying and treating preventable causes of decline, says Allman, who is principal investigator of the UAB Study of Aging, a prospective observational study of 1000 community-dwelling adults aged >65 years sponsored by the National Institute on Aging.
The cohort is balanced in gender, urban-rural residence, and race (50% African American, 50% white). Investigators recruited participants from a random sample of Alabama Medicare recipients and have completed 6 years of follow up.
Mobility and Life-Space
Mobility is the most common functional problem reported by older adults. “Mobility is an important predictor of adverse health outcomes and mortality among this population,” Allman says. “Functional evaluation is key to capturing a picture of older patients’ current health, but traditional assessments that measure activities of daily living [ADL] often are not sensitive enough to detect problems early, when they may be reversible.”
Most elders — up to 80% of people older than 85 years — do not report problems toileting, bathing, and dressing, for example. “They may, however, have marked reductions in mobility,” he says. As part of the UAB Study of Aging, Allman and colleagues developed the life-space assessment (LSA), a highly sensitive tool for detecting changes in older adults’ mobility, which is strongly associated with their global health status (Physical Therapy. 2005;85:1008-1019).
The study found changes in life space are correlated with traditional measures of day-to-day function, depression, and cognitive health. Life-space, Allman says, can be conceptualized as a pattern of areas defined by distance extending from the location where a person sleeps (See Figure 1). By measuring a person’s mobility, including use and frequency of assistance, in their home and community, physicians can determine baseline levels of mobility and track sudden or gradual reductions. These changes can signify significant shifts in health status. “Life-space assessment goes beyond straightforward evaluation of ambulation and physical function and picks up other factors that can adversely affect mobility, such as cognitive decline and changes in socioeconomic status,” he says.
Unlike performance-based tests, the LSA, a questionnaire that can be administered in person or by telephone in about 5 minutes, measures “what people actually do and how they do it rather than their performance of certain functions during formal assessments or their perception of their daily activities,” Allman says.
“People may unconsciously adapt to mobility limitations by gradually restricting life-space,” he says. “They may, for example, say that they are not having trouble getting around when they are having a friend drive them on errands. They may compare themselves to peers who are hospitalized or in nursing homes and believe and report they are doing fine, when in fact they are limiting their mobility because of a new medical, cognitive, socioeconomic, or emotional issue.”
Mobility as a domain of functional decline is a trigger for further evaluation. “When physicians detect reductions in mobility they should not dismiss them as inevitable consequences of aging,” Allman says. “Some declines are unavoidable, but often changes indicate a new, potentially modifiable problem. Life-space assessment can help clinicians identify older patients who need further evaluation as well as interventions to optimize function and independence.”
The UAB Study of Aging has found that the odds of dying during a 6-month period more than double for every standard deviation decrease in life space. LSA is designed to evaluate a person’s mobility in the 4 weeks preceding assessment. Scores range from 0 to 120, with higher values indicating greater mobility. Over 3 years, investigators found persons with a LSA score ≥60 had a 10% mortality rate. As LSA scores declined, death rates rose: mortality was 20% for individuals with scores between 30 and 60, and those with scores <30 had a mortality rate of 30%.
“Life-space assessment provides valuable prognostic information,” Allman says. Recently analyzed 6-year follow-up data from the UAB study showed mortality increased as baseline LSA scores decreased, rising from 17% to 33% to 58% for persons with baseline LSA scores >80, 40-80, and <40, respectively.
“Diabetes is one of the most significant independent predictors for life-space decline in people older than 65,” Allman says. “Secondary complications of diabetes — retinopathy and kidney disease, for example — also predict decline. Improving diabetes management in older patients and preventing the disease in younger people are essential components of helping people preserve mobility and independence.”
Hospital-Associated Decline
Allman notes that for patients ≥65 years and older, life-space typically falls 1 to 2 points per year, with much larger decreases beginning at age 76 years. More research is needed to explain this precipitous drop, but Allman hypothesizes that acute events — new strokes, falls, or cancers, for example — probably explain rapid declines.
“Hospitalizations may be another significant factor,” he says. A yet-to-be-published analysis by UAB Study of Aging investigators found individuals admitted to hospitals experience sizeable life-space declines. “People admitted for surgery, including major procedures, lose an average of 15 points of life-space,” he says. “Yet, we found these individuals tend to return to their baseline life-space scores, and some even gain a few points.”
Patients admitted for nonsurgical care, however, lost about 10 points of life space and had not regained baseline mobility after 2 years of follow up. Loss of strength may be a possible cause of hospital-related life-space decline.
Allman says, “Healthy young people lose about 1% of their strength per day when confined to bed — older people, especially sick older people, lose much more. Other factors, including inadequate nutrition and hospital–acquired infection, can contribute to long-term functional decline,” he says.
In addition, 30% of hospitalized older patients develop delirium, which is associated with reductions in life-space and significant increases in mortality.
“Older adults often have mild cognitive impairment that is not recognized on hospital admission. These patients are at high risk for delirium, which can be caused by inappropriate medication, dosages that are not titrated for older individuals, and unnecessary use of restraints,” Allman says.
Avoiding hospital-associated morbidity and linked declines in mobility will require changes in care before, during, and after admission, he says. “Older patients need early orientation, active and frequent mobilization, and careful monitoring of their nutritional status as well as age-appropriate medications and avoidance of restraints to prevent delirium.”
Once patients go home, careful discharge planning is required to prevent readmission, another significant cause of morbidity. “Older people have complex medical needs that require close management and coordination of care — something our current health care system does not deliver adequately,” he says. “By recognizing and responding to changes in their patients’ global health status, physicians can help their patients age successfully, which for many means maintaining independence with the best-attainable levels of cognitive and physical function.”
For more information:
Dr. Richard Allman
1.800.UAB.MIST
mist@uabmc.edu