An increased risk of major ischaemic events among autistic people

Background Autistic people have increased risks of cardiometabolic conditions, even after accounting for known risk factors such as obesity, substance use, and age, as well as an increased risk of premature of mortality. However, no studies specifically assess risks of major ischaemic events among autistic people. Purpose To determine whether autism is associated with an increased risk of major ischaemic events, if it remains an independent predictor of this after accounting for demographics and other cardiovascular risk factors, and identify if these events are happening earlier in life. Methods This is a retrospective cohort study from 1/1/1990 to 31/12/2019 with 23,565 autistic people matched 1:5 by birth year (± 2 years), general practitioner practice ID, and gender to 117,825 non-autistic people. Electronic health records were leveraged from the Clinical Practice Research Datalink and Hospital Episode Statistics, as well as demographic and death registration data from the Office of National Statistics in the United Kingdom. The primary exposure of interest was a clinical diagnosis of autism. Secondary exposures included health conditions associated with ischaemic disease that are included in QRISK3 with some additional conditions relevant to autism. The outcome measured was the occurrence of major ischaemic events which was composed of myocardial infarction, angina, other ischaemic heart disease, stroke, and transient ischaemic attacks. Results The autistic population were 1.29 (95%CI: 1.11, 1.50) times more likely to have a major ischaemic event after accounting for all factors. There was a small attenuation in risk of a major ischaemic event across modelling, though autism remained significant across all models. In the male-only analysis, the male cohort were 1.22 (95%CI: 1.03, 1.45) more likely to have a major ischaemic event, we were unable to conduct female-only analyses due to sample size. The age at first event had a bimodal distribution in autistic and non-autistic cohorts. However, the autistic cohort had a dominant first peak, having their first event younger. Several health conditions associated with ischaemic disease also had a significantly higher prevalence among the autistic cohort such as severe mental illness, dyslipidaemia, and obesity. Conclusion Autistic people have an increased risk of major ischaemic events and need improved risk management. While some of this risk can be attributed to known cardiovascular risk factors, the majority remains unexplained. The risk of a major ischaemic events were further reduced when performed on males only, suggesting a difference in risk profiles between sexes. The autistic population also had their first event at a younger age, highlighting the importance of earlier intervention. As ischaemic disease is a primary cause of death globally, research is urgently needed to better understand this relationship and to identify appropriate interventions for reducing risk.