Premature mortality in intellectual disability in Australia (and England)

"Adults with ID [intellectual disability] experience premature mortality and over-representation of potentially avoidable deaths."

The paper by Julian Trollor and colleagues [1] (open-access available here) provides some sombre reading today, as once again the topic of early mortality is raised on this blog. Looking at several measures - the "Age Standardised Mortality Rate (ASMR), Comparative Mortality Figure (CMF), years of productive life lost (YPLL) and proportion of deaths with potentially avoidable causes" - authors paint a depressing picture of a 'mortality gap' between those diagnosed with a learning (intellectual) disability and the wider, general population.

I don't want to trawl through the Trollor paper in great detail given that it is open-access for all to see, but a few points are worthwhile raising. So, based on data from some 20,000 adults (aged 20 or over) registered with an intellectual disability (ID) in New South Wales (NSW) in Oz, there were 732 deaths reported (4%) "equivalent to a crude death rate of 5.9 deaths per 1000 people per year." The median age at death was 54 years and about 60% of deaths were in men. A control cohort consisting of adults from NSW was used as a comparator where "a crude death rate of 9.1 deaths per 1000 person years" was calculated. The median age at death however, for the control group, was 81 years. When looking at death rates between the groups according to age banding (20-44 years, 45-64 years, 65+ years) authors noted that: "People with ID in the 20–44 years age category had four times the death rate of the comparison group."

Looking at the causes of death between the ID and control groups, authors noted some potentially important trends. So: "Cause of death in [the] ID cohort was dominated by respiratory, circulatory, neoplasm and nervous system." This bearing in mind that cause of death was not available for everyone diagnosed with an ID (only 87%). Such causes were not wildly different from those noted in the control population but when it came to 'potentially avoidable deaths' the ID group were placed at some quite notable disadvantage, with 31% of deaths falling into this category (revised up to 38% depending on the 'death classification' used) compared with 17% in the general population. Readers should also note that: "Potentially avoidable deaths are deaths from conditions that are preventable through individualised care and/or treatable through existing primary or hospital care for persons aged under 75 years and which are avoidable in the context of the present health system."

As you can see, there are some quite shocking details noted in the Trollor paper. The emerging picture that some of the most vulnerable people in society (certainly in Australia) are (a) at risk of dying earlier than the general population and (b) at greater risk of suffering a 'potentially avoidable death' is one that no-one should be proud of. And just in case you though the results might not be generalisable to other parts of the world... you're wrong [2] (open-access here) as data from England reveals that: "Mortality rates for people with ID were significantly higher than for those without. Their all-cause standardised mortality ratio was 3.18. Their life expectancy at birth was 19.7 years lower than for people without ID." Truly shocking.

What can society do about such a state of affairs? Well, potentially lots (and it doesn't take monumental shifts to achieve better outcomes either). "Particularly stark is the large proportion of
potentially avoidable deaths due to infections. Such deaths suggest that people with ID experience delays, difficulties or differences in accessing specific and effective interventions for infections. Medical assistance must be sought assertively in individuals who manifest symptoms, but this is made difficult as patients with ID may not readily report symptoms, and some providing direct care
lack skills in early identification of relevant physical signs. Primary care providers should consider careful assessment, proactive treatment and close monitoring of progress if there are infections in this population." Sorry for the large chunk of replication text there but several important themes are laid out by Trollor, some of which overlap with other work in relation to autism for example (see here). Not least is the need for 'proactivity' on the part of clinicians and other professionals, potentially dealing with a group who may not be able to readily communicate their physical state for example and so shifting the responsibility on medical care being inspective and proactive. This means regular health screening and, at the basic level, understanding that a diagnosis of ID (or autism or schizophrenia [3]) does not seemingly provide any protection against the development of life-threatening illness or other conditions becoming evident.

I close with an article discussing another part of the reason why people with ID are being placed at an unacceptably high risk of early death: when those who are supposed to provide care, fail.

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[1] Trollor J. et al. Cause of death and potentially avoidable deaths in Australian adults with intellectual disability using retrospective linked data. BMJ Open. 2017. Feb 7.

[2] Glover G. et al. Mortality in people with intellectual disabilities in England. J Intellect Disabil Res. 2017 Jan;61(1):62-74.

[3] Hjorthøj C. et al. Years of potential life lost and life expectancy in schizophrenia: a systematic review and meta-analysis. Lancet Psychiatry. 2017 Feb 22. pii: S2215-0366(17)30078-0.

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Trollor J, Srasuebkul P, Xu H, & Howlett S (2017). Cause of death and potentially avoidable deaths in Australian adults with intellectual disability using retrospective linked data. BMJ open, 7 (2) PMID: 28179413