Increased risk of major ischaemic events among autistic people

Importance: Autistic people have increased risks of cardiometabolic conditions and premature mortality; however, no studies specifically assess risks of major ischaemic events in the autistic population. Objective: To determine whether autistic people are at increased risk of major ischaemic events after accounting for known risk factors. Design: A retrospective matched cohort study from 1/1/1990 to 31/12/2019. Cox regression models accounting for matching factors, sociodemographic characteristics, intellectual disability, and cardiovascular risk factors were employed. Setting: This population-based study leveraged lifetime primary and secondary care electronic health records from the Clinical Practice Research Datalink and Hospital Episode Statistics, as well as sociodemographic, ethnicity, and death registration data from the Office of National Statistics. Participants: 23,612 autistic people were matched 1:5 on birth year (+/-2 years), general practitioner practice ID, and gender to 118,060 non-autistic people. Autistic people were defined as those with a clinical autism diagnosis recorded during the study period. Patients missing Indices of Multiple Deprivation and ethnicity data, and an end date prior to their CPRD start date were excluded along with their matched set. Exposure: Clinical diagnosis of autism. Secondary exposures included health conditions associated with cardiovascular disease with some additional conditions relevant to autism. Main Outcome and Measures: Time to first major ischaemic event (any of myocardial infarction, angina, other ischaemic heart disease, ischaemic stroke, and transient ischaemic attacks). Results: Autistic people had a greater risk of a major ischaemic event in the study period in the minimally adjusted Model 1 (HR 1.19; 95% CI: 1.00, 1.42) as well as for autistic females even after accounting for risk factors (adjusted HR 1.71; 95% CI: 1.10, 2.67). There was also evidence that several cardiometabolic risk factors had a higher prevalence among the autistic group such as severe mental illness, dyslipidaemia, and obesity (all P<0.001). Conclusions and Relevance: Autistic people have an increased risk of major ischaemic events and need improved cardiometabolic risk management. This risk remained in autistic women after adjusting for cardiometabolic and sociodemographic factors. As cardiovascular disease is a primary cause of death globally, research is needed to better understand the mechanism that drives this association.