Life Expectancy in Severe Disability

Description

Severity of disability affects life expectancy, but many children with severe disablities live well into adulthood, and some have normal life expectancies. This article explores the evidence relating disability and life expectancy.

Learning objectives

Impact of nutrition on developmental disabilities

Know predictive factors in life expectancy in individuals with severe disability, particularly ability to feed independently.

"My patient with multiple disabilities died recently and I am trying to find out what is the life expectancy in a child with multiple severe disabilities. The patient referred to me was male age 21 years. He had been born very premature, experienced chronic lung disease, and developed spastic quadriplegia, severe cognitive impairment, and oral/pharyngeal dysphagia. He had epilepsy, controlled by phenobarbital. He died suddenly overnight and vomitus was found on the side of his face." (DBP Discussion Group, June 6, 2000)

The Problem

What developmental diagnostic category best predicts mortality? What functional abilities most affect mortality risk? What are typical causes of death? Some literature does exist that addresses life expectancy in persons with severe disabilities. We now know more about the problem than just the average age of death for level of abnormality.

The Evidence

Eyman et al (1990) reported on 99,543 persons with developmental disabilities who obtained services from the California Department of Developmental Services between March 1989 and October 1997. Data was based on Client Development Evaluation Reports (CDER). All had cognitive impairment. Mental retardation (MR) was the handicapping condition of focus. Functional abilities that related statistically to mortality were degree of ambulation, mobility, toileting skills, eating skills, and tube feeding. Immobile persons could not crawl, creep, or scoot in prone. Persons were unable to feed if they needed to be fed completely by others.

If a person had severe or profound mental retardation, was immobile, not toilet trained, and was tube fed, then life expectancy was, on average, only 4 or 5 years more than the current age for those persons between the ages of 1 and 24 years at the start of the study. Mobility, or immobility, was the best single predictor of mortality risk. If others could feed a person with immobility then life expectancy doubled. If some functional mobility was also present, then life expectancy doubled again. Finally using the above categories of handicap and function, the addition of presence of seizures or of cerebral palsy (CP) did not alter the predictions of mortality.

Hutton et al(1994) evaluated 1251 cases of cerebral palsy born between 1966 and 1984 in the Mersey region of England, using hospital and community records. Functional abilities evaluated were ambulatory ability, manual dexterity, and mental ability. If severe mobility impairment (required a wheelchair and assistance for propulsion), severe manual dexterity impairment (inability to feed and dress without assistance), and severe mental impairment (Intelligence Quotient <50) were all present, then average life expectancy was 17-20 years. Again impairment of mobility was the best single predictor. Severity of mental impairment was least predictive of these three functional classifications.

Strauss and Shavelle(1999) reported on the life expectancy of adults (persons age 15 years or over) with a diagnosis of cerebral palsy. The population, again, was from the California Department of Developmental Services consisting of 182,623 persons with developmental disabilities who received services from January 1980 to December 1995. Eight functional abilities were evaluated; rolling/sitting, hand use, ambulation, feeding, severity of CP, severity of MR, type and location of CP, presence of epilepsy, and speech and communication. Life expectancy beyond age 15 years was only 7.8 more years for persons both unable to lift his head and tube fed. If one was able to be fed by others but still unable to lift one's head, then life expectancy was 11.3 years beyond 15 years of age.

Strauss et al (1997) using the same data set as their report on life expectancy of adults with cerebral palsy, and the UCP Research Foundation (1995), using data from death certificates provided by the National Center for Health Statistics/USPHS for the year 1987, addressed the cause of death in persons with cerebral palsy. This is of particular interest since the assumption generally is that severe motor impairment resulting in poor mobility and poor feeding skills also place one at much higher risk for death from respiratory compromise and aspiration. Indeed, respiratory causes underlie 15 to 45 per cent of deaths, a wide range due to the imprecise nature of data collection. Another large category was circulatory system or heart disease.

Summary

Anticipating the death of a person with severe functional impairments is imprecise. There are several controversies, such as the effects of institutional or community placement or of when and how tube feeding is used (Blacher 1998; Strauss 1997). A family member's ability to cope with the death of a loved one who has severe developmental disability, family financial planning, medical-legal malpractice awards, and state and federal disability budgets are all affected by these uncertain estimates.

Functional motor impairment so severe that head control and rolling or scooting mobility and oral feeding ability all are poor appears to result in drastically reduced life expectancy. Conversely, persons with developmental disability of cognitive or neuromuscular function who have some functional mobility or ambulation and have some functional oral feeding skills seem to have only mildly or moderately reduced life expectancies, depending in part on the degree of functional impairment. Function, rather than diagnostic category, seems to be most predictive of early mortality.

Dr. Hoffman is a Developmental-Behavioral Pediatrician in Kansas City, Missouri, and a member of the Section on Developmental and Behavioral Pediatrics

Available media

Life Expectancy in Severe Disability

References

UCP Research Foundation. Causes of death of persons with disabilities due to cerebral palsy. UCPnet (http://www.ucp.org) 1995. [98]
Strauss D, Cable W, Shavelle R. Causes of excess mortality in cerebral palsy. Dev Med Child Neurol 1999;41:580-585 [95]
Hutton JL, Cooke T, Pharoah POD. Life expectancy in children with cerebral palsy. BMJ 1994;309:431-435 [94]
Strauss D, Shavelle R. Life expectancy of adults with cerebral palsy. Dev Med Child Neurol 1998;40:369-375 [97]
Blacher J. Much ado about mortality: Debating the wrong question. Ment Retard 1998;36:412-415. [92]
Eyman RK, Grossman HJ, Chaney RH, Call TL. The life expectancy of profoundly handicapped people with mental retardation. N Engl J Med 1990;323:584-589 [93]
Strauss D, Kastner T, Ashwal S, White J. Tube feeding and mortality in children with severe disabilities and mental retardation. Pediatrics 1997;99:358-362 [96]