Rates, causes and predictors of all-cause and avoidable mortality in 163,686 children and young people with and without intellectual disabilities: A record linkage national cohort study
Authors: Hughes-McCormack Laura , Rydzewska Ewelina , Cooper Sally-Ann , Fleming Michael , Mackay Daniel , Dunn Kirsty , Ward Laura , Sosenko Filip , Barlow Fiona , Miller Jenny , Symonds Joseph D , Jani Bhautesh D , Truesdale Maria , Kinnear Deborah , Pell Jill , Henderson Angela , Melville Craig 
Published: August 2022

Objectives

To investigate mortality rates and associated factors, and avoidable mortality, in children/young people with intellectual disabilities.

Design

Retrospective cohort; individual record-linked data between Scotland’s 2011 Census to 9.5 years of National Records for Scotland death certification data.

Setting

General community.

Participants

Children and young people with intellectual disabilities living in Scotland aged 5-24 years, and an age matched comparison group.

Main outcome measures

Deaths up to 2020: age of death, age-standardised mortality ratios (age-SMRs); causes of death including cause-specific age-SMRs/sex-SMRs; and avoidable deaths.

Results

Death occurred in 260/ 7,247 (3.6%) children/young people with intellectual disabilities (crude mortality rate=388/100,000 person years), and 528/156,439 (0.3%) children/young people without intellectual disabilities (crude mortality rate=36/100,000 person years). SMR for children/young people with, versus those without, intellectual disabilities were 10.7 for all causes (95% confidence interval (CI)=9.47-12.1), 5.17 for avoidable death (CI=4.19-6.37), 2.3 for preventable death (1.6-3.2), and 16.1 for treatable death (CI=12.5-20.8). SMRs were highest for children (27.4, CI=20.6-36.3) aged 5-9 years, and lowest for young people (6.6, CI=5.1-8.6) aged 20-24 years. SMRs were higher in more affluent neighbourhoods. Crude mortality incidences were higher for the children/young people with intellectual disabilities for most ICD-10 chapters. The most common underlying avoidable causes of mortality for children/young people with intellectual disabilities were epilepsy, aspiration/reflux/choking and respiratory infection, and for children/young people without intellectual disabilities, were suicide, accidental drug-related deaths and car accidents.

Conclusion

Children with intellectual disabilities had significantly higher rates of all cause, avoidable, treatable, and preventable mortality than their peers. The largest differences were for treatable mortality, particularly at ages 5-9 years. Interventions to improve health-care to reduce treatable mortality should be a priority for children/young people with intellectual disabilities. Examples include improved epilepsy management and risk assessments, and co-ordinated multi-disciplinary actions to reduce aspiration/reflux/choking and respiratory infection. This is necessary across all neighbourhoods.

Strengths and limitations of this study

Novel use of Census records and record linkage to death records to study mortality in a total population cohort of children and young people with intellectual disabilities.

Due to the use of a whole country population, these results are well-powered and generalisable.

Despite comprising a whole country population, our study was not large enough to delineate cause-specific mortality ratios by sex.

This study was limited by lack of demographic and clinical diagnostic information, including the severity or cause of intellectual disabilities.

Reliance on death certificate data is limited by inconsistencies in reporting of cause of death.