While an in-depth understanding of internal medicine serves as a foundation, proper care of older adults should be complemented by insight into the multidimensional effects of aging on disease manifestations, consequences, and response to treatment. In younger adults, individual diseases tend to have a more distinct pathophysiology with well-defined risk factors; the same diseases in older persons may have a less distinct pathophysiology and are often the result of failed homeostatic mechanisms. Causes and clinical manifestations are less specific and can vary widely between individuals. Therefore, the care of older patients demands an understanding of the effects of aging on human physiology and a broader perspective that incorporates geriatric syndromes, disability, social contexts, and goals of care. For example, care planning for the older patient cannot ignore the influence of life expectancy. In fact, the expected remaining years of life can guide recommendations about appropriate preventive and other long-term interventions, and shape discussions about treatment alternatives.
Demography (Chap. 70) Population aging emerged on a worldwide scale for the first time in history within the last century. Since aging influences many facets of life, governments and societies now face new social and economic challenges that impact health care, as well as family and community responsibilities. Figure 72-1 highlights recent and predicted changes in U.S. population structure. The overall number of children has remained relatively stable, but explosive growth has occurred among older populations. The percentage growth is particularly dramatic among the oldest old. For example, the 80–89-year-old group increased more than threefold between 1960 and 2010 and will increase almost tenfold between 1960 and 2050. Women already outlive men by many years and the sex discrepancy in longevity is projected to increase further in the future.
Change in the structure of the U.S. population between 1960 and 2050. (From United Nations World Population Prospects: The 2008 Revision, http://esa.un.org/unpp.)
Population aging occurs at different rates in varying geographic regions of the world. Over the last century, Europe, Australia, and North America have had the populations with the greatest proportions of older persons, but Asia and South America are aging rapidly, with a population structure that will resemble the "older" countries by around 2050 (Fig. 72-2). Among older persons, the oldest old (those older than age 80 years) are the fastest growing segment of the population (Fig. 72-3), and the pace of aging is projected to accelerate in most countries in the next 50 years. There is no evidence that the rate of population aging is decreasing.
Population aging in different geographic regions. (From United Nations World Population Prospects: The 2008 Revision, http://esa.un.org/unpp.)
Percentage of the population age >80 years from 1950 to 2050 in different representative nations. The pace of aging will accelerate. (From United Nations World Population Prospects: The 2008 Revision, http://esa.un.org/unpp.)
Population Aging and Health
Many chronic diseases increase in prevalence with age. It is not unusual for older persons to have multiple chronic diseases (Fig. 72-4) although some seem more susceptible to co-occurring problems compared to others. Functional problems with difficulty or need for help in performing basic activities of daily living (ADLs) (Table 72-1) increase with age and are more common in women than men. In recent decades, the age-specific prevalence of disability has declined, especially in the oldest old. Estimated rates are shown in Fig. 72-5 as the percentage of persons who reported severe difficulty or needed help in bathing, but data on other basic activities of daily living show similar trends. The rate of decline in disability is decreasing, but the magnitude of this decline is small compared to the overwhelming effect of population aging. Thus, the number of people with disability in the United States and other countries is rapidly expanding. Rates of cognitive impairments, such as memory problems, also increase with aging (Fig. 72-6). Chronic disease and disability lead to increased use of health care resources. Health care expenditures increase with age, increase more with disability, and are highest in the last year of life. However, new medical technologies and expensive medications are greater influences on health care costs than population aging alone. General practitioners and internists with little specific training in geriatric medicine provide the bulk of care for older persons.
Prevalence of comorbidity by age group in persons 65 years and older living in the U.S. and enrolled in Medicare parts A and B in 1999. (From JL Wolff et al: Arch Intern Med 162:2269, 2002.)
Self-reported prevalence of disability (severe difficulty) in bathing/showering between 1992 and 2007, according to age and sex. (From Medicare Current Beneficiary Survey 1992–2007. Accessed May 26, 2010 at http://22.214.171.124/HDI/TableViewer/.)
Table 72-1 Basic and Instrumental Activities of Daily Living
| Save Table
Table 72-1 Basic and Instrumental Activities of Daily Living
|The Basic Activities of daily living (ADLs) consist of these self-care tasks|
- Personal hygiene
- Dressing and undressing
- Transferring from bed to chair, and back
- Voluntarily controlling urinary and fecal discharge
- Using the toilet
- Moving ...
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