Cause of death and potentially avoidable deaths in Australian adults with intellectual disability using retrospective linked data

Abstract

Objectives: To investigate mortality and its causes in adults over the age of 20 years with intellectual disability (ID).

Design, setting and participants: Retrospective population-based standardised mortality of the ID and Comparison cohorts. The ID cohort comprised 42 204 individuals who registered for disability services with ID as a primary or secondary diagnosis from 2005 to 2011 in New South Wales (NSW). The Comparison cohort was obtained from published deaths in NSW from the Australian Bureau of Statistics (ABS) from 2005 to 2011.

Main outcome measures: We measured and compared Age Standardised Mortality Rate (ASMR), Comparative Mortality Figure (CMF), years of productive life lost (YPLL) and proportion of deaths with potentially avoidable causes in an ID cohort with an NSW general population cohort.

Results: There were 19 362 adults in the ID cohort which experienced 732 (4%) deaths at a median age of 54 years. Age Standardised Mortality Rates increased with age for both cohorts. Overall comparative mortality figure was 1.3, but was substantially higher for the 20-44 (4.0) and 45-64 (2.3) age groups. YPLL was 137/1000 people in the ID cohort and 49 in the comparison cohort. Cause of death in ID cohort was dominated by respiratory, circulatory, neoplasm and nervous system. After recoding deaths previously attributed to the aetiology of the disability, 38% of deaths in the ID cohort and 17% in the comparison cohort were potentially avoidable.

Conclusions: Adults with ID experience premature mortality and over-representation of potentially avoidable deaths. A national system of reporting of deaths in adults with ID is required. Inclusion in health policy and services development and in health promotion programmes is urgently required to address premature deaths and health inequalities for adults with ID.

Keywords: Cause of death; Cohort studies; Intellectual disability; Mortality; Record linkage.

Figure 1

Age-specific avoidable death rates in people with and without ID. X Axis: Age group. Y Axis: Age-specific death rate (per 1000 persons). ABS, Australian Bureau of Statistics; ID, intellectual disability.