Mortality in people with intellectual disabilities in England

Abstract

Background: People with intellectual disabilities (IDs) die at younger ages than the general population, but nationally representative and internationally comparable mortality data about people with ID, quantifying the extent and pattern of the excess, have not previously been reported for England.

Method: We used data from the Clinical Practice Research Datalink database for April 2010 to March 2014 (CPRD GOLD September 2015). This source covered several hundred participating general practices comprising roughly 5% of the population of England in the period studied. General practitioner (GP) records identified people diagnosed by their GP as having ID. Linked national death certification data allowed us to derive corresponding mortality data for people with and without ID, overall and by cause.

Results: 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. Circulatory and respiratory diseases and neoplasms were the three most common causes of death for them. Cerebrovascular disease, thrombophlebitis and pulmonary embolism all had standardised mortality ratios greater than 3 in people with ID. This has not been described before. Other potentially avoidable causes included epilepsy (3.9% of deaths), aspiration pneumonitis (3.6%) and colorectal cancer (2.4%). Avoidable mortality analysis showed a higher proportion of deaths from causes classified as amenable to good medical care but a lower proportion from preventable causes compared with people without ID. International comparison to areas for which data have been published in sufficient detail for calculation of directly standardised rates suggest England may have higher death rates for people with ID than areas in Canada and Finland, and lower death rates than Ireland or the State of Massachusetts in the USA.

Conclusions: National data about mortality in people with ID provides a basis for public health interventions. Linked data using GP records to identify people with ID could provide comprehensive population-based monitoring in England, unbiased by the circumstances of illnesses or death; to date information governance constraints have prevented this. However, GPs in England currently identify only around 0.5% of the population as having ID, suggesting that individuals with mild, non-syndromic ID are largely missed. Notably common causes of death suggest control of cardiovascular risk factors, epilepsy and dysphagia, management of thrombotic risks and colorectal screening are important areas for health promotion initiatives.

Keywords: England; cause of death; intellectual disability; international comparisons; life expectancy; mortality.