Disease and mortality trajectories of cognitively able autistic individuals in mid- and later adulthood.

Background: An increasing number of autistic adults have entered their later life, but little is known about the disease trajectory in mid- and later adulthood. We aimed to examine the patterns of comorbidity progression in adults with autism spectrum disorder (ASD) that may affect their mortality.

Methods: Participants were identified from the UK Biobank study. We first identified individuals with ASD diagnosis, each of whom was randomly matched to up to 10 participants without ASD diagnosis. Cox regression was used to estimate the hazard ratio (HR) of mortality. Disease trajectory analysis was performed to investigate temporal sequencing of medical conditions and mortality associated with ASD. A multistate model was used to investigate the association patterns between ASD and three common chronic conditions: cardiovascular disease/hypertension, type 2 diabetes and disorders of lipoprotein metabolism, and depression/anxiety.

Results: The study included 659 ASD cases (66.8% male; mean age 52.0 [SD, 8.1]) and 6590 matched non-autistic individuals. ASD were associated with a 90% higher all-cause mortality (HR, 1.90, 95% CI, 1.41-2.55) and also higher risks of 45 medical conditions across almost all body systems (all Bonferroni-adjusted P < 0.05). Trajectory analyses exhibited three clusters of medical conditions that predisposed autistic adults to excess mortality: cardiometabolic diseases, external conditions, and infectious diseases. Autistic adults showed not only an overall increased risk of progression of multimorbidity but also distinctive association patterns across different disease transitions.

Conclusions: Our findings show patterns of comorbidities among autistic adults in their mid- and later adulthood, which could provide information to their caregivers to implement appropriate disease management and prevention strategies.