5
Secondary Conditions and Aging with Disability

I was about 35 years old when I started to feel the signs of aging that I later learned were being brought on prematurely by my disability (cerebral palsy). The timing was ironic, because it coincided with my involvement as the principal investigator of one of the country’s first studies of how disability affects the [process of aging]…. I became aware that I wasn’t alone with these symptoms, that they weren’t ‘all in my head.’ But I was frightened because aging with a disability was an uncharted course.

Kathleen Lankasky (2004 [used with permission])


One surprising and sometimes frightening feature of life with certain potentially disabling conditions acquired at birth or in early life is that people who have managed their lives successfully for years may find, as they reach their 30s or 40s, that they are experiencing the effects of aging earlier than others or are developing secondary health conditions.1 This is not what they had expected. For clinicians, researchers, policy makers, and others, the challenge is, on the one hand, to prevent or delay secondary conditions and premature aging and, on the other hand, to prepare for and mitigate their effects, once they develop. Meeting this challenge will involve progress on several fronts, including improving professional and consumer awareness and responses based on existing knowledge, strengthening further that base of knowledge, developing supportive public policies, and identifying and removing environmental barriers such as inaccessible transportation systems.

1

As discussed later in this chapter, secondary health conditions are additional physical or mental health conditions—such as pressure ulcers or urinary tract infections—that can result from a primary health condition but that are not a diagnostic feature of that condition.



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The Future of Disability in America 5 Secondary Conditions and Aging with Disability I was about 35 years old when I started to feel the signs of aging that I later learned were being brought on prematurely by my disability (cerebral palsy). The timing was ironic, because it coincided with my involvement as the principal investigator of one of the country’s first studies of how disability affects the [process of aging]…. I became aware that I wasn’t alone with these symptoms, that they weren’t ‘all in my head.’ … But I was frightened because aging with a disability was an uncharted course. Kathleen Lankasky (2004 [used with permission]) One surprising and sometimes frightening feature of life with certain potentially disabling conditions acquired at birth or in early life is that people who have managed their lives successfully for years may find, as they reach their 30s or 40s, that they are experiencing the effects of aging earlier than others or are developing secondary health conditions.1 This is not what they had expected. For clinicians, researchers, policy makers, and others, the challenge is, on the one hand, to prevent or delay secondary conditions and premature aging and, on the other hand, to prepare for and mitigate their effects, once they develop. Meeting this challenge will involve progress on several fronts, including improving professional and consumer awareness and responses based on existing knowledge, strengthening further that base of knowledge, developing supportive public policies, and identifying and removing environmental barriers such as inaccessible transportation systems. 1 As discussed later in this chapter, secondary health conditions are additional physical or mental health conditions—such as pressure ulcers or urinary tract infections—that can result from a primary health condition but that are not a diagnostic feature of that condition.

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The Future of Disability in America Secondary conditions related to a primary health condition and atypical or premature aging with disabilities are important because they can affect physical and psychosocial functioning, independence, and participation in community life, including work. They can diminish a person’s quality of life, add to the demands on family members or others as caregivers, expose previously unnoticed environmental barriers that limit activity and participation, and challenge health care professionals whose education has not prepared them to care knowledgeably for people aging with early-onset or long-standing disabilities. As noted in Chapters 3 and 4, more and more children and young adults with once fatal conditions that contribute to disability are surviving into middle and late life, thus increasing the number of individuals at risk for secondary conditions and premature or atypical aging. Some individuals are also at risk of long-term complications of treatment, including treatments (e.g., chemotherapy, radiation, and surgery) that were undertaken to cure or mitigate their condition. On the basis of data from the 1994–1995 Disability Supplement to the National Health Interview Survey, Verbrugge and Yang (2002) estimated that approximately 7 to 9 percent of adults had a disability that began before age 20 (Table 5-1). Approximately 20 to 30 percent of adults experienced the onset of their disability between ages 20 to 44. An analysis of Canadian data reported that approximately two-thirds of people ages 65 to 74 who had a disability had acquired that disability before age 65, whereas for people age 75 and older, the figure was less than 30 percent (HRSDC, 2005). Focused interest in secondary conditions and aging with disability is relatively recent and reflects, in part, the survival and life expectancy trends for children and adults noted above. Citing the attention-directing observations of Michael Marge (1988), the Institute of Medicine (IOM) report Dis- TABLE 5-1 Age of Disability Onset for Individuals with Disabilities by Category of Disability, 1994 Type of Disability Percentage of Individuals with Disability Onset at Age: At birth >0–19 20–24 25–44 45–65 65–74 75+ ADL 4.1 4.5 2.7 18.3 25.2 18.9 26.3 IADL 3.9 4.9 3.2 22.3 29.4 18.8 17.5 PLIM 2.3 5.1 4.1 27.0 31.7 16.7 13.1 NOTE: ADL = limitation in activities of daily living; IADL = limitation in instrumental activities of daily living; PLIM = limitation in physical tasks. Data are from the National Health Interview Survey Disability Supplement, Phase 1 (1994), and are weighted to be representative of the U.S. civilian noninstitutional populations ages 18 and older. Row distributions add to 100 percent. SOURCE: Verbrugge and Yang (2002 [used with permission]).

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The Future of Disability in America ability in America (1991) devoted a chapter to secondary conditions. Both the 1991 report and the report Enabling America (IOM, 1997) recognized aging as a risk factor for secondary conditions and noted that interventions that prevent secondary conditions will promote health and well-being as people with disabilities grow older. A number of other reports, articles, and conferences have explored these topics, including the 2005 workshop and associated publication sponsored as part of the activities used to develop this report (Treischmann, 1987; Simeonsson and McDevitt, 2002; Kemp and Mosqueda, 2004; IOM, 2006b). In addition, the National Institute on Disability and Rehabilitation Research has funded three relevant research centers, one focusing on aging with a disability, a second one focusing on aging with developmental disability, and a third one focusing on secondary conditions. Longitudinal research that can guide consumer health practices and clinical care is still in short supply, but at least the rationale for such research is better understood. The significance of secondary conditions as a legitimate target for public health strategies is also evident in Healthy People 2010, which includes a chapter on disability and secondary conditions (CDC, 2001). An overarching goal stated in that report is to “promote the health of people with disabilities, prevent secondary conditions, and eliminate disparities between people with and without disabilities in the U.S. population” (p. 6-8). The goals do not explicitly mention aging with disability, but discussions of secondary conditions and aging with disability (including those reviewed in this chapter) often overlap and cite the same health issues and literature. Efforts to prevent secondary conditions or to delay and slow the progression of conditions linked to aging with certain kinds of disability are a form of tertiary prevention (IOM, 1991). In a public health or clinical context, primary prevention aims to avert the creation or onset of illnesses, injuries, or other conditions (e.g., through vaccination programs to prevent polio and other contagious diseases and through the promotion of folic acid use during pregnancy to prevent spina bifida). For health conditions that are already present but that are either not recognized or not symptomatic, secondary prevention emphasizes early detection and intervention to halt or delay the progression of the condition (e.g., through screening for breast cancer and through infant testing and the use of early dietary interventions to prevent symptoms of phenylketonuria). Tertiary prevention seeks to reduce or stabilize the consequences of a primary health condition and prevent or mitigate secondary health conditions associated with a primary condition. Examples of tertiary prevention include evaluating the bone density of young people with mobility impairments such as cerebral palsy to prevent fractures from secondary osteoporosis, monitoring individuals who have had a stroke for shoulder pain, and educating individuals with sensory impairments on the selection and safe use of assistive technologies.

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The Future of Disability in America In addition to clinical care, tertiary prevention may involve environmental modifications, such as changes in household technologies or arrangements that reduce the risk of falls or that help a person remain independent in self-care. Tertiary prevention also extends to the policy arena, for example, through the removal of barriers and hazards in public spaces and the adoption of policies that help people pay for home modifications or assistive technologies. These outcomes may also benefit family members and society generally. Although scientific and clinical knowledge about secondary conditions and aging with disability has advanced and strategies for preventing additional disabilities have improved, much remains to be learned—and to be applied consistently where knowledge does exist. Before selected segments of the research literature on secondary conditions and aging with a disability are reviewed, the next section puts these aspects of living with disability in a broader framework. A LIFE SPAN PERSPECTIVE ON SECONDARY CONDITIONS AND AGING WITH A DISABILITY In discussions of disability across the life span, one frequent goal is to draw attention to the long-term aspects of living with a disability. As people with many kinds of chronic health conditions acquired in early, middle, or late life live longer and as the impact on later life of what happens earlier in life is more fully appreciated, clinicians, families, and people with disabilities are recognizing how important it is to consider and plan for the long-term future. Experience and research have prompted reconsideration of some traditional ways of managing and living with certain conditions to reduce unwanted long-term effects. For example, as Kemp and Mosqueda (2004) have written, “instead of encouraging everyone [with conditions such as polio or cerebral palsy] to work as hard as possible … ‘the use it or lose it attitude’ … a philosophy akin to ‘conserve it to preserve it’ may be more appropriate” (p. 4). This shift reflects one theory behind postpolio syndrome, which holds that after the initial assault of the polio virus, the remaining motor neurons are overworked, particularly during intensive and prolonged exercise. Unfortunately, clinicians and consumers with postpolio syndrome still lack solid scientific evidence about the role of exercise, including how to strike a balance between sufficient exercise for the prevention of illnesses such as cardiovascular disease and sufficient rest for the prevention of severe fatigue and weakness. This example underscores points made in earlier chapters. First, longitudinal studies are vital, and second, consideration of the long-term future should start soon after the onset of a potentially disabling condition. In

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The Future of Disability in America addition, given the impact on later life of what happens earlier in life, evaluations of adults with long-standing disabilities should also consider the long-term past (Verbrugge and Yang, 2002). That is, it is important for clinicians to obtain thorough medical and personal histories from these adults, even though it may be difficult to document some elements of the past. People with childhood-onset conditions may not know key details about the onset of their condition, its initial treatment, and potentially relevant environmental circumstances, such as exposure to toxic substances. Their parents likewise may not remember or may not be alive, and childhood medical records may not be available. The implications of aging with a disability and the potential for acquiring a secondary condition vary by the nature of an individual’s primary health condition. Later sections of this chapter review several conditions for which data on secondary conditions and aging are comparatively good. Although the discussion in this chapter focuses on the medical and cognitive aspects of aging with disability, the committee recognizes the need to better understand the role of environmental and personal factors in premature or atypical aging. Lankasky (2004) has, for example, stressed such psychosocial issues as helping children with disabilities to develop a strong sense of self-worth that will prepare them for sometimes negative attitudes from peers, health care professionals, and others. Others have also pointed to the influence of personal factors, in particular, styles of coping with adversity (see, e.g., Hansen et al. [1998]) and family circumstances (see, e.g., Kemp et al. [1997] and Kemp [2006]) in shaping an individual’s responses to declines in health or functioning. Secondary Conditions In 1988, Michael Marge observed that people with disabilities are at significant risk for “additional or secondary disabilities” (Marge, 1988). The 1991 IOM report (p. 35) defined secondary condition as “any additional physical or mental health condition that occurs as a result of having a primary disabling condition.”2 (A “disabling condition” is any mental 2 Others have defined the term far more broadly to include many additional possible consequence of a primary disabling condition, such as social isolation or a lack of romantic relationships (see, e.g., DHHS [2000a]). Nonetheless, just as this report distinguishes primary physical or mental health conditions from poverty, pollution, discrimination, and other environmental conditions that may contribute to illness, injury, impairment, activity limitations, or participation restrictions, so, too, does it distinguish secondary physical or mental health conditions from the social and economic consequences that may follow the onset of a primary health condition. Excluding unwanted social and economic outcomes from the definition of secondary conditions does not, in any sense, diminish their significance or the importance of taking steps to help people lead rewarding social lives.

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The Future of Disability in America or physical health condition that can lead to disability.) Some secondary conditions, for example, depression, arthritis, and cardiovascular disease, are also common primary health conditions (see, e.g., Kemp [2006]). In the clinical and research literature, frequently mentioned secondary conditions include arthritis, pain, pressure ulcers, fatigue, depression, contractures, and urinary tract infections. The risk of developing a particular secondary condition, however, depends in part on a person’s primary condition. For example, people who have vision or hearing impairments are generally not at higher-than-average risk of pressure ulcers or urinary tract infections. As is the case with a primary disability, the interaction of biology, lifestyle and behavior, and environmental factors affect whether a secondary condition contributes to the development of additional impairments, activity limitations, or participation restrictions. Some secondary conditions, such as an infected pressure ulcer, can become life-threatening, and some can be more disabling than the primary condition, for example, when intractable pain causes someone to cut back on work or social activities. One challenge for researchers, who are still building a descriptive base of knowledge on secondary conditions, is sorting out the contributions of different health, personal, and environmental factors to these conditions. People with a given primary health condition will not necessarily experience all the secondary conditions for which they are at increased risk, especially if good preventive strategies exist and are used. For those who do develop them, severity may vary. For example, not all children with cerebral palsy will have contractures, and among those who do, some children will have more severe contractures than others. Again, individuals’ experiences may reflect the specific features of their primary condition, the quality of their medical and rehabilitative services, their ability to adhere to treatment or prevention regimens, their access to personal care assistance, and other personal and environmental factors. Many secondary conditions appear to be linked through common physiological processes or functional characteristics across several different primary health conditions. For example, as discussed later in this chapter, people with significant mobility limitations—which might be related to spinal cord or brain injury, multiple sclerosis, or a number of other conditions—are at risk of pressure ulcers or contractures. As more longitudinal research is undertaken, more linkages and common risk factors may be identified. Likewise, long-term clinical or well-designed observational studies may identify the extent to which common interventions (e.g., prescribed exercises) can reduce the probability or severity of secondary conditions that are common to different primary health conditions (see, e.g., Rimmer and Shenoy [2006]). Discussions of secondary conditions are complicated by confusion with

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The Future of Disability in America several other types of health conditions. According to the definitions offered by Turk (2006), associated conditions are aspects or features of the primary condition; that is, they are expected elements of its pathology, although their expression may be variable. Thus, for people with cerebral palsy, spasticity is an aspect of upper motor neuron impairment and, therefore, an associated rather than a secondary condition. Although many people with cerebral palsy do not experience them, seizures and mental retardation are also considered features of the disorder’s pathology and not secondary conditions. To cite other examples, limited skin sensation is an associated condition with spinal cord injury. Dysphagia is an associated condition of Parkinson’s disease and other disorders that affect the muscles or nerves used in swallowing, such as amyotrophic lateral sclerosis. Muscle weakness is a defining feature of post-polio syndrome. Clinically, an inability to make distinctions between features of the primary health condition and secondary conditions may not affect individual patient care. Another distinction is between secondary conditions and comorbidities. Comorbidities are health conditions that develop independently of the primary condition. They are neither a feature of the condition nor a secondary condition. A person with a traumatic brain injury may develop skin cancer. An individual with hearing loss may develop heart disease. Sometimes, however, researchers identify links between conditions formerly thought to be independent of each other. One example is the link between spinal cord injury and the development of insulin-resistant diabetes, as discussed later in this chapter. Treatment complications are caused by treatment for a condition rather than by the condition itself. Like secondary conditions, they may sometimes be preventable. Also like secondary conditions, they can contribute to additional disability. In practice and especially over the long term, it can be difficult to distinguish treatment effects, secondary conditions, and age-related phenomena. Age may affect the development and treatment of secondary conditions. For example, although secondary conditions such as pressure ulcers or recurrent urinary tract infections can occur at a very young age, prevention or management may be more difficult with older people who have less physiological reserve capacity, more comorbid chronic conditions, and other age-related changes, such as thinning of the skin. In addition, age may make a person more susceptible to the side effects of treatment, such as gastrointestinal bleeding in association with the use of nonsteroidal anti-inflammatory drugs for treatment of pain (see e.g., Laine et al. [2002] and Pilotto et al. [2003]).

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The Future of Disability in America Aging and Disability I write … [as] someone who is a living, aging-with-disability ‘laboratory.’… When I talk with older people without disabilities about their aging experiences, I often identify with what they describe and think to myself, ‘I’m already there!’ June Isaacson Kailes (2006) Although genetics, environment, and behavior contribute to significant variations in individual patterns of aging, aging as a biological process begins at a relatively young age. For example, declines in muscle mass, hormone levels, organ function, and other biological structures or processes begin well before people reach their 50s (see, e.g., Masoro [1999] and Schulz et al. [2006]). Over a normal life span, such natural physiological declines are not preventable, although they may be accelerated or slowed by a variety of individual genetic factors, personal behaviors (e.g., diet and exercise), health care practices (e.g., screening and treatment for heart disease), and other environmental circumstances (e.g., working conditions). In most discussions about disability and in most disability-related research, a focus on aging typically means a focus on the increasing level of chronic illness and disability in late life. That is, the emphasis is on people aging into disability. In contrast, the emphasis in this chapter is on aging with a disability, which typically refers to the experience of people who were born with physical or mental impairments or who acquired them in early to middle life. A Canadian government report limits the description to people under the age of 65 (HRSDC, 2005). Understanding and studying the nature of aging with disabilities requires an appreciation of the different dimensions of time that may be at work (see, e.g., Campbell [1993] and Krause and Adkins [2004]). These dimensions include the usual process of development and aging through childhood, middle life, and late life; the number of years spent with a particular disability, for example, having lived with multiple sclerosis for 10 years, whether its onset occurred at age 25 or age 35; in some cases, the years of exposure to a particular medication (e.g., corticosteroids) or other therapy or environmental factor with cumulative adverse side effects; the individual’s cohort or era of disability onset and initial medical treatment, which may be associated with different treatment experiences,

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The Future of Disability in America attitudes, and opportunities, depending, for example, on whether the individual experienced a traumatic brain injury in 1985, 1995, or 2005; and the age at onset of a disability in relation to the individual’s developmental maturity. The last factor—the age of onset in relation to developmental maturity—may be important for some conditions, such as a spinal cord injury, that typically involve prolonged periods of hospitalization for acute treatment and rehabilitation. A 5-year-old, for example, is dealing with different developmental tasks than a 15-year-old, which means that younger and older children may experience different long-term psychosocial or physical effects from an extended hospitalization. In addition, the severity of a condition sometimes varies with the age at onset. As the list above suggests, a variety of mechanisms likely explain the aspects of aging with a disability considered in this chapter. For example, for disabilities that typically lead people to compensate for impairments in one aspect of the body with additional demands on other aspects of the body (e.g., people with impairments in lower limb mobility compensate with greater reliance on their arms and shoulders), the existence of a disability for a longer period of time may accelerate use-related musculoskeletal pain or other problems. The time that a person lives with a disability may also interact with the metabolic or other biological processes and changes triggered by a primary health condition, leading eventually to the earlier-than-usual development of, for example, cardiac or orthopedic problems. SELECTIVE REVIEW OF THE LITERATURE Despite the many complexities and questions surrounding the definition of secondary conditions, consumers, practitioners, and researchers have adopted the concept as a useful way of understanding certain potentially preventable health conditions that can contribute to additional disability. Researchers are generating an increasing amount of information about secondary conditions, usually in studies of specific primary health conditions, such as spinal cord injury. Likewise, researchers are investigating the experiences of people aging with different kinds of primary health conditions. In addition, researchers are recognizing that a number of primary conditions, particularly those involving musculoskeletal impairments, show certain common patterns of secondary conditions or aging, although the underlying pathophysiologies may vary. In some cases, better understanding of these kinds of common patterns may lead to interventions that are effective for people with a range of primary health conditions. The research reviewed in this section focuses on secondary conditions, but much, if not most, of this research has also been considered in presentations or papers about aging with disability. The research largely involves

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The Future of Disability in America disabilities and impairments that have relatively high prevalence rates (e.g., cerebral palsy), are easy to associate with a disability group (e.g., polio survivors), benefit from organized and dedicated service programs (e.g., spinal cord injury), and—reflecting these characteristics—have attracted research funding sufficient to generate a significant body of knowledge about the condition. Most studies focus on biological and clinical processes and health outcomes. Some consider or acknowledge the contribution of environmental or personal factors, such as a lack of health insurance coverage for relevant services or equipment (e.g., a proper wheelchair), inaccessible fitness equipment and facilities, or the failure of individuals or their caregivers to follow preventive or treatment regimens (e.g., recommended exercises and proper positioning in a bed or a chair). They may emphasize a particular secondary condition, such as pain, or they may consider multiple conditions. Few consider activity and participation outcomes or effects on family members. The research reviewed here suffers from various other limitations. The literature includes a combination of scientifically observed and anecdotal information. Secondary conditions are sometimes the central focus of research; but they may also be noted in descriptive studies, reports on the health status or life course of people with disabilities, and health promotion studies. For the most part, studies are cross-sectional rather than longitudinal, although a few have focused on aging and the life course for specific chronic conditions. They often involve convenience samples or case series that may not be representative of the larger population of individuals with a particular disability. Studies that include more than one primary condition may have a higher representation of people with certain conditions and may not report data for each condition group, so it may be difficult or inappropriate to generalize about each group. Still, methodologically sound cross-condition studies in areas such as exercise interventions may be useful to the extent that the biological processes of the response to the intervention are similar. Another limitation of much research is that conclusions are drawn from patient reports and clinical observations without the use of standardized measures of individual characteristics or outcomes. A few studies use a very broad definition of secondary conditions and include disability-related social conditions, such as unemployment or social isolation. Embedded in these studies, however, may be useful descriptive information about secondary health conditions. Further complicating the picture, some research describes as secondary conditions what this report describes as associated conditions (e.g., poor urinary control and incontinence in individuals with spinal cord injuries) or direct residuals of the primary impairment (e.g., behavior dysregulation in individuals with brain injuries). Again, a critical

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The Future of Disability in America review may sort out such labeling differences to glean useful descriptive information about secondary conditions from these reports. The review in the following sections is illustrative rather than comprehensive. It covers research on secondary conditions associated with four specific primary conditions that have been the focus of considerable research and other attention: spinal cord injury, cerebral palsy, postpolio syndrome, and Down syndrome. The review also considers some cross-condition studies. Spinal Cord Injury The typical person experiencing a spinal cord injury is a young male (National Spinal Cord Injury Statistical Center, 2006). Better early treatment of spinal cord injuries has led to improved survival, although often with severe long-term impairments. In addition, better treatment of certain associated and secondary conditions, including urinary tract complications, has increased survival beyond the initial treatment stage. Young survivors can typically expect decades of living—and aging—with the disability. The secondary conditions and aging experiences of individuals with spinal cord injuries are probably the best defined of all disability groups. Many medical centers have organized spinal cord injury centers or programs, and both institutions and professionals may be certified or credentialed to provide these services. These organized and focused care settings can support systematic data collection, surveillance, and ongoing research, including research on secondary conditions. Research on spinal cord injury has been consistently funded through the model systems programs of the National Institute on Disability and Rehabilitation Research and the National Center for Medical Rehabilitation Research and through the Veterans Health Administration with support from the Paralyzed Veterans of America. (Chapter 10 discusses the desirability of better coordination of the model systems programs supported by the National Institute on Disability and Rehabilitation Research and National Center for Medical Rehabilitation Research model.) Because a spinal cord injury involves multiple organ systems, many of the associated health conditions (as defined earlier) are often erroneously identified as secondary conditions. For example, neurogenic bladder and bowel can be expected in people with spinal cord injuries and may involve either over- or underactive functioning. Autonomic dysreflexia (overactivity of the autonomic nervous system, leading to dangerously high blood pressure), is possible in injuries at and above the sixth thoracic vertebra (approximately waist level), and spasticity can be anticipated in 70 percent of people with spinal cord injuries (Levi et al., 1995). Each of these medical conditions is a residual of the injury, that is, an associated condition.

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The Future of Disability in America include cardiac and gastrointestinal anomalies and abnormalities. Children with Down syndrome have a 15-fold increased risk for leukemia and hematological aberrations (Lange, 2000; see also Kivivuori et al. [1996] and Roizen and Patterson [2003]). Molecular studies have not yet provided an explanation for this predisposition to leukemias for children with Down syndrome. Older individuals with Down syndrome are often more obese, are of shorter stature, and have more medical problems than older individuals with other cognitive conditions (Carmeli et al., 2004). According to an analysis of mortality data conducted by the Centers for Disease Control and Prevention, life expectancy for people with Down syndrome increased at a rate of almost 2 years per year from 1968 to 1997 (Friedman, 2001). The analysis also identified a very large gap in the median life expectancies of whites and blacks with the condition: 57 years for whites and only 25 years for blacks. The data did not help in identifying the source of this disparity, except to suggest that it did not appear that it was associated with differences in life-threatening malformations or congenital heart conditions and likely was associated with poor access to health care and other environmental factors. As their life expectancy has increased, people with Down syndrome are experiencing an array of new physical and mental conditions in middle and late life. In clinical terms, these conditions probably include a mix of associated conditions (i.e., conditions that are aspects of the primary condition but that were not commonly seen until life expectancy increased) and secondary conditions related to aging or environmental factors (e.g., low levels of physical activity). People with Down syndrome experience higher rates or the earlier onset of hearing loss, cataracts, and endocrine disorders (e.g., diabetes mellitus). Thyroid function requires monitoring into adulthood, since the signs of hypothyroidism can be confused with dementia (Smith, 2001). Although cardiac abnormalities are usually diagnosed in infancy and childhood, adults with Down syndrome without known cardiac disease can develop valve dysfunction (Cohen and Patterson, 1999). Obstructive sleep apnea occurs in up to 50 percent of individuals with Down syndrome (Southall et al., 1987; Stebbens et al., 1991) and is related to obesity, decreased muscle tone, and structural abnormalities (Smith, 2001). A recent review of the literature reported that individuals aging with Down syndrome are more likely than the rest of the population to develop Alzheimer’s disease in middle age (Connolly, 2006). Furthermore, some research suggests that postmenopausal women with Down syndrome and low serum estrogen levels are four times more likely to develop Alzheimer’s disease than women with Down syndrome and higher hormone levels (Schupf et al., 2006). Because of this increased risk for Alzheimer’s disease, physicians may jump to the conclusion that the symptoms of people with Down syndrome are related to Alzheimer’s disease and fail to evaluate other potential causes (e.g., depression, bladder incontinence because of nar-

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The Future of Disability in America rowing of the spinal canal, and memory problems related to medications). Other medical or health conditions may also be overlooked. These include hypothyroidism, drug effects, delirium, and myelopathy. Obesity is common in people with Down syndrome, and people with the condition are known to have reduced resting metabolic rates (Luke et al., 1994; Allison et al., 1995). Although research has not confirmed their effectiveness, suggested prevention strategies include the monitoring of growth, the adjustment of food selections, the promotion of exercise, and the use of behavioral techniques (Roizen and Patterson, 2003). Also well known are the low muscle tone and joint laxity associated with Down syndrome. If joint instability is detected clinically or radiographically, individuals with Down syndrome may be placed under activity restrictions, especially those related to sports activities. Several follow-up studies of children with asymptomatic instability have, however, shown no development of subluxation or spinal cord compression with and without sports activity restrictions (Pueschel et al., 1992; Cremers et al., 1993a,b). Research also suggests that cervical myelopathy has an earlier onset in adults with Down syndrome (Bosma et al., 1999) and that outcomes from surgical stabilization vary (Doyle et al., 1996; Bosma et al., 1999; Taggard et al., 2000). To encourage the early identification and management of various conditions associated with Down syndrome, the American Academy of Pediatrics (AAP, 2001) and the Down Syndrome Medical Interest Group (Cohen and Patterson, 1999) have developed guidelines for pediatricians and family practitioners. Specific recommendations include routine immunizations; cardiac evaluation with echocardiogram before 6 months of age; audiologic evaluation, including a tympanogram, by 6 months of age; screening of newborn infants with Down syndrome for hypothyroidism and periodic testing for hypothyroidism throughout childhood and into adulthood; and ophthalmological evaluations beginning in infancy and routinely thereafter, given that ophthalmological disorders increase in frequency with age in individuals with Down syndrome (Roizen et al., 1994; Cohen and Patterson, 1999). Cross-Condition Studies The discussion earlier in this chapter noted a number of secondary conditions that appear to be related not to a specific disease but to functional impairments, such as muscle weakness and limited use of muscles. Some studies have directly investigated secondary conditions among people with different primary health conditions. The objectives of such research include the identification and understanding of the association of these primary conditions with common secondary conditions and the extent to

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The Future of Disability in America which the latter might be responsive to common preventive or therapeutic interventions (see, e.g., Ravesloot et al. [2006], Rimmer and Shenoy [2006], and Seekins et al. [2006]). Most studies have involved people with physical mobility disabilities, with little representation of individuals with sensory-related conditions (e.g., vision impairment and hearing impairment) or cognitive disabilities. Some studies use a broad definition of secondary conditions that covers social participation (see, e.g., Ravesloot et al. [2006] and Seekins et al. [2006]). Most studies employ survey or questionnaire methods of data collection. Several cross-condition studies (Seekins et al., 1994; Ravesloot et al., 1997; Wilber et al., 2002; Kinne et al., 2004; Nosek et al., 2006) have identified three common secondary conditions: fatigue, chronic pain, and depression. Other conditions listed in these studies—such as spasticity or spasms, weakness, and mobility impairments—may represent associated conditions. Sleep problems and eating or weight control issues are also named, but with various rates of prevalence or identification, depending on the study. Nevertheless, each study offers insights into the associations between these conditions and health status, activities, and participation. Individuals with a larger number of secondary conditions tend to have poorer health outcomes and poorer general health status (Wilber et al., 2002). Individuals with spinal cord injuries report more secondary conditions than other groups (Wilber et al., 2002), and women reported more interference in activities from secondary conditions (Nosek et al., 2006). Using a different approach, Chan and colleagues (2005) investigated the secondary conditions occurring in a large sample of Medicare beneficiaries with motor performance disabilities. That study showed a high prevalence of secondary conditions, although, again, the conditions examined included both secondary conditions and impairments from the primary disability (e.g., dysphagia, spasms, and weakness). Musculoskeletal system-related conditions were more common than other conditions. Higher levels of mobility and limitations in activities of daily living were associated with a higher number of secondary conditions and an increased need for the medical management of those secondary conditions. DIRECTIONS FOR RESEARCH AND EDUCATION The research reviewed above focused on a few primary health conditions for which considerable data on secondary conditions and aging are available. The review reveals an increasing knowledge base as well as knowledge gaps. Gaps also exist in the education of health care professionals in caring for people with serious chronic conditions and disabilities.

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The Future of Disability in America Research Challenges, Knowledge Gaps, and Research Directions The identification of secondary conditions or atypical aging with a disability depends on the understanding of the etiology and pathophysiology of particular primary conditions and the expected trajectory (or range of trajectories) of health and function typically associated with such conditions. Thus many studies are disability specific. The ability to generalize about aging and secondary conditions for multiple disability groups is difficult without an in-depth understanding of the linkages among common physiological processes, functional characteristics, or the underlying pathophysiology to a set of primary health conditions. For example, people with a variety of chronic health conditions experience similar associated and secondary conditions in the musculoskeletal and neuromuscular realms. Spasticity, contractures, and pain are common among people with spinal cord injuries, multiple sclerosis, cerebral palsy, brain injuries, and stroke. In the realm of function, problems such as fatigue, falls, and a decline in one’s ability to handle daily activities, such as dressing or bathing, are common among people with these and several other primary conditions. In contrast, with a number of more traditional medical problems, such as bladder dysfunction, it may be difficult to make generalizations across impairment groups. People with damage at the spinal cord level have difficulty with bladder function arising from a physiological mechanism different from that in people with bladder dysfunction caused by brain pathology (e.g., cerebral palsy, stroke, or a brain injury). Thus a common functional characteristic may have different pathophysiological sources. This complexity requires research that identifies such differences in ways that are relevant to clinical practice. Some challenges relate to data collection and measurement. Large databases often rely on patient reports of medical conditions, which may result in the misclassification of conditions. For example, people may report that they have arthritis as an additional medical problem, when a problem with pain or stiffness may actually stem from soft tissue musculoskeletal conditions rather than joint abnormalities. Such reporting errors may result both from a patient’s assumptions and from health professionals’ misunderstanding of the patient’s signs and symptoms. A different challenge and need is the involvement of people with disabilities in establishing priorities for research; developing research questions and emphases; and, when they are qualified, participating as investigators, contributors, collaborators, and managers (Kailes, 2006). To the extent that clinical or other researchers focus primarily on medical aspects, they may overlook the basic issues of functioning and social participation that matter the most to people aging with a disability or grappling with secondary conditions. The involvement of family members and caregivers may

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The Future of Disability in America likewise be valuable both in identifying outcomes relevant to those close to an individual with disabilities and in developing a fuller understanding of secondary conditions; aging issues; and potentially constructive clinical, environmental, and other interventions. As discussed earlier in this chapter, pain is a common secondary condition for adults with many chronic conditions, and recent studies note that pain is also present in children with cerebral palsy (Tervo et al., 2006). Given that shoulder pain is a common complaint of those who propel wheelchairs over a long period of time and that pain and osteoarthritis are noted in the intact knees of those with lower limb amputation over time (Hungerford and Cockin, 1975; Norvell et al., 2005), a theoretical basis exists for a rehabilitation focus on prevention as well as performance-enhancing strategies. To date, however, there has been no direct study of the effect of rehabilitation and therapeutic strategies focused on the conservation of physiological capacity and function. Also in need of further development more generally are evaluations of prevention and intervention programs. In general, health and function monitoring is inconsistent clinically. Unless an index of suspicion exists, clinicians may not routinely question individuals to identify changes in health and performance. Moreover, the interventions typically prescribed are those strategies used for the treatment of similar conditions in individuals without disabilities. That is, the principles of treatment for shoulder derangement syndromes for people without disabilities are used for the treatment of shoulder dysfunction in people who propel wheelchairs, with some modifications (e.g., advice to use a power wheelchair instead of a manually propelled wheelchair). These interventions have been seen to be effective on the basis of anecdotal evidence or case reports but have not been systematically evaluated. Other interventions are even less well supported. Use of medications that are commonly prescribed for menopausal osteoporosis to reduce bone resorption or increase bone formation have shown some promise for the treatment of secondary osteoporosis in children with osteogenesis imperfecta (a genetic disorder associated with weak, easily broken bones) and in women with spinal cord injuries, but the long-term benefits and effectiveness of these medications in preventing bone mineral loss are unclear. Research directions therefore involve several fronts. These include further study and classification of secondary and aging conditions related to specific primary health conditions; classification of secondary conditions and conditions associated with aging with a disability that are common across primary health conditions, with the identification of the similar and the different physiological origins of the secondary problems;

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The Future of Disability in America clarification of the extent to which different kinds of levels of functioning and performance in earlier life are associated with the development of secondary and aging conditions; evaluation of prevention and intervention strategies, including the use of assistive technologies, exercise, medications, and environmental modifications; assessment of the effects of secondary conditions and aging with a disability on family members and caregivers; and systematic reviews of the literature, with the consolidation, development, and dissemination of practice guidelines. The second direction cited above has implications for the design and conduct of research. To the extent that certain secondary conditions are strongly linked to functional characteristics, such as limitations in mobility, this implies the need for more cross-condition research. As noted earlier in this chapter, groups have developed evidence-based practice guidelines for specific conditions related to individuals with spinal cord injuries. In general, however, these guidelines apply to an adult population with spinal cord dysfunction and are specific to the identified condition (e.g., autonomic dysreflexia, urinary tract infections, and neurogenic bladder). They are not intended to broadly guide the monitoring and promotion of general health and functioning. For childhood-onset conditions and disabilities, it is particularly important that guidelines describe anticipatory care to identify and prevent common secondary health and aging conditions that may develop in the decades after the onset of the primary condition. Some examples of monitoring and anticipatory care guides for children with disabilities can be cited (see, e.g., Ohio Department of Health [1995a,b,c,d] and the Down syndrome guidelines noted earlier [Cohen and Patterson, 1999; AAP, 2001]). Overall, despite the increasing amount of information available, only a limited number of standards and quality markers now exist to help physicians, especially primary care physicians, monitor their patients with disabilities for common preventable or manageable aging and secondary conditions. Education of Health Care Professionals Although a critical review of the similarities and differences in secondary conditions and aging conditions among categories of disability was beyond the resources of this committee, it is clear that clinical care for some groups has undergone a paradigm shift as longer life spans have brought new questions and new research. In general, as people with early-onset disabilities grow older, the conservation of function and the prevention of secondary conditions become high priorities.

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The Future of Disability in America In the committee’s experience, despite the availability of increased amounts of information about secondary conditions and aging with disability and changes in care for some conditions, primary care and other clinicians outside the field of rehabilitation continue to display a limited appreciation of both concepts. This limitation is subsidiary to broader deficiencies in clinical education about chronic care management, as discussed in Chapter 4. These deficiencies extend to education about both general and specialized health promotion and preventive care needs of people with disabilities. Today, the basic medical curriculum generally includes little meaningful content specific to disability, as it is defined in this report. Most medical school graduates have minimal experience providing care to people with long-term disabilities. Among the medical and other health care professions, few beyond physical medicine and rehabilitation, physical therapy, and occupational therapy have comprehensive clinical requirements relating directly to the provision of health care for people with disabilities. Education theory identifies attitudes, knowledge, and skills as requirements for competent patient care; and undergraduate, graduate, and continuing education for health care professionals is important in each of these three areas. Research on the provision of care for people with disabilities has noted negative attitudes among health care providers, but has also documented that education about disability and experience with people with disabilities creates more positive attitudes (Estes et al., 1991; Gething, 1992; Lindgren and Oermann, 1993; Oermann and Lindgren, 1995; Rainville et al., 1995; Ralston et al., 1996; White and Olson; 1998; Packer et al., 2000; Chan et al., 2002; Tervo et al., 2002). Such attitudes are important for the establishment of unbiased approaches to history taking, the performance of physical examinations, and the consideration of nonmedical issues and supports, such as home and family environments. The committee recognizes the intense competition for space in an already crowded medical curriculum but believes that it is important for clinicians to have a basic grounding in disability concepts and issues common to the care of people with disabilities, including routine primary care, the prevention and management of secondary conditions and premature aging, the provision of timely referrals, and respectful attention. The better dissemination of existing knowledge is also important. Currently, publications about secondary conditions and issues related to aging with a disability appear in a variety of journals or search formats but often without these terms appearing as key words. The consolidation of existing information and the design of more usable electronic and other formats could increase the dissemination of information to clinicians and the use of that information by clinicians. In addition, tools or systems that could be used to monitor changes in an individual’s health and functioning over time would be of significant assistance to clinicians and people with disabilities.

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The Future of Disability in America Systematic reviews of the research in this area would provide a credible evidence base for practice guidelines, monitoring systems, best practices, and quality markers. RECOMMENDATIONS Since the publication of the 1991 IOM report on disability, clinicians, consumers, researchers, and the public health community have—to various degrees—become more aware of and knowledgeable about secondary health conditions and aging with disability. Nonetheless, clinicians need better preparation, awareness, and evidence-based guidance to manage the care for their patients with disabilities and advise their patients about these conditions and processes. The guidance developed for clinicians will often not be directly useful to consumers but can provide a foundation for the development of additional resources for individuals with disabilities and their families. The committee’s recommendations focus on organizing the knowledge base and improving professional education. Organizing the Knowledge Base In addition to continuing research to expand the knowledge base about secondary conditions and aging with disability, it is important to organize that knowledge in ways that are useful to both professionals and consumers. As exemplified in the PVA-sponsored guidelines for the prevention of secondary conditions related to spinal cord injuries, this will likely involve different information products and different dissemination strategies for these two groups. Organized knowledge in the form of evidence-based reviews is an important starting point. Such reviews will likely need to be framed in two different ways. One way will be with a focus on a particular primary health condition and what is known about related secondary conditions and aging. The other will be with a focus on secondary conditions and aging issues that are common to several primary conditions. In some cases, separate reviews may be needed for children or other groups if comprehensive documents would be unwieldy or unlikely to reach key audiences. The committee believes that people with disabilities and clinicians, including rehabilitation specialists, would benefit from additional systematic assessments of the evidence as a basis for developing practice guidelines or critical pathways for the prevention and management of secondary conditions or the care of people aging with disabilities. One feature of such reviews should be the identification of practices for which evidence is lacking. Given its experience in managing evidence-based reviews to support the development of clinical practice guidelines, the Agency for Healthcare Re-

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The Future of Disability in America search and Quality in the U.S. Department of Health and Human Services is well situated to oversee this activity and to involve other government agencies, professional societies, advocates, and researchers in identifying priorities for systematic reviews. The Agency for Healthcare Research and Quality also sponsors a clinical practice guidelines clearinghouse that is a useful vehicle for disseminating guidelines (see http://www.guideline.gov). The agency has identified people with disabilities as a priority population for its health services research agenda (Clancy and Andresen, 2002). New work focused on secondary conditions and aging with a disability would require additional resources. Recommendation 5.1: The U.S. Congress should direct and fund the Agency for Healthcare Research and Quality so that it may take the lead in evaluating the evidence base to support the development of clinical practice guidelines, quality goals, and monitoring standards for the prevention and management of secondary health conditions among people with disabilities and for the monitoring and management of people aging with a disability; evaluating the evidence base about environmental contributors to secondary health conditions; and identifying research gaps and directions for further research on secondary health conditions and aging with a disability. Improving the Education of Health Care Professionals As noted in the 1991 IOM report, “[m]ost schools of medicine, nursing, and allied health have not properly prepared health care professionals to address problems and issues related to disability and chronic disease” (p. 231). In the committee’s experience and judgment, too little progress has occurred since then. The committee recognizes that health care professions programs face challenges in better preparing professionals in these areas, especially generalists and others who do not specialize in rehabilitation or the provision of health care for individuals with specific chronic health conditions. Those designing curricula face the challenge, not only of including basic medical and health knowledge, but also covering leading-edge information regarding the multiplying medical advances in areas such as genomics, pharmacology, and materials science that may be applicable to people with disabilities. Even with a fairly long period of physician training, competition is fierce for space in didactic educational modules or coverage during clinical rotations. In this competition, education and experience involving care for people with disabilities have fared poorly. Recent graduates tend to be better versed in management of acute medical conditions,

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The Future of Disability in America and seasoned clinicians often become focused on limited practice areas that direct their self-study. The available information on disabilities thus tends to be disseminated to a restricted audience. Given the expected growth in the numbers of people aging with disability or aging into disability and the increasingly understood opportunities for clinical care and guidance to prevent or mitigate secondary conditions, health care professions education has a critical role to play. The building of a knowledge base about disability should begin early in a clinician’s education and training and be reinforced through direct clinical experience with people with disabilities. Physicians who do not routinely care for patients with disabilities still need core knowledge and skills and appropriate support systems (see Chapter 4), for example, to guide the provision of timely and accessible preventive care services, the prevention of secondary conditions, and the referral of patients with disabilities to experts with more specific knowledge, when appropriate. The committee recognizes that the increased knowledge required of health care professionals can be daunting and that they often welcome evidence-based reviews and well-crafted, evidence-based guidelines for practice that help them maintain and update their knowledge and skills. In addition, accreditation, certification, and licensing boards and agencies have required documentation of self-assessment and lifelong learning to promote excellence in health care, and guidelines and evidence-based reviews may also be useful for that purpose. Health plans have also developed or adopted guidelines or similar tools to monitor services and to promote cost-effective care, and they are increasingly seeking to couple provider payment to performance using such tools, which may or may not be based on systematic reviews of the relevant evidence and well-designed consensus development methods. Given the discussion of cross-condition interventions earlier in this chapter, screening and other prevention or treatment approaches and guidelines may increasingly be focused on functional limitations (e.g., lower extremity weakness) as well as on primary conditions. Recommendation 5.1 calls for the evaluation of evidence to support the development of guidelines and pathways to improve the health care of people with disabilities. Recommendation 5.2 calls for the development of such guidelines and for the formulation of disability-related educational modules and competency standards for health care professionals. The principles for the development of evidence-based practice guidelines have been articulated elsewhere, including in three IOM reports (IOM, 1990a, 1992, 1995). Involvement by professional societies, researchers, and advocates in the process should be useful in developing guidance that will be helpful to different categories of clinicians, health care organizations, and health care professions educators. Different formats and contents may be appropriate for different purposes and audiences, for example, clinical generalists versus

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The Future of Disability in America rehabilitation specialists. Once guidelines are developed for professionals, the development of additional documents for people with disabilities and their family members should be considered. Recommendation 5.2: As part of broader efforts to improve the quality of care provided to people with disabilities, health care professionals, educators, people with disabilities, and their family members should work together to develop, disseminate, and apply guidelines for the prevention and management of secondary conditions and for the monitoring and care of people aging with disability; design educational modules and other curriculum tools for all relevant types of health care professionals and all levels of education; and develop competency standards for these educational programs. Even with improved guidance and information, well-informed clinicians, and knowledgeable consumers, the maintenance of health and functioning can be difficult in the face of the environmental barriers that people with disabilities often encounter in daily life and in health care environments. These barriers include inaccessible transportation that can make health care appointments difficult, hazards in the home, information technologies that are unfriendly to people with sensory and other impairments, insurance plans that limit access to technologies that increase safety and functioning, and inaccessible health care equipment and facilities. The next several chapters (and Appendixes D through G) discuss aspects of these environmental barriers.