Mortality rates among hospitalized individuals with autism spectrum disorder over a 10-year period in the 100 Million Brazilian Cohort

ABSTRACT Introduction: This study aims to investigate the main causes of mortality among individuals hospitalized with Autism Spectrum Disorder (ASD) and to estimate the association between ASD hospitalization and mortality rates over a 10-year period (2008–2018). Method: This is a population-based cohort study using linked administrative health data and social assistance system (CadÚnico) records from the 100 Million Brazilian Cohort. The study included 948 individuals hospitalized with an ASD diagnosis and 99,904 non-hospitalized individuals. Cox proportional hazards regression was estimated using propensity scores to allow balanced comparisons between groups (ASD / non-ASD). Results: Individuals hospitalized with ASD died more frequently from respiratory (24%) and neurological (20%) diseases, whereas non-hospitalized individuals died more from circulatory diseases (27.8%) and neoplasms (17.1%). Hospitalized individuals with ASD had an overall higher risk of death (HR = 1.78, 95%CI = 1.20–2.66, p = 0.005), particularly females (HR = 3.48, 95%CI = 1.95–6.19, p < 0.001), those aged 11–24 years (HR = 3.20, 95%CI = 1.45–7.06, p = 0.004), and those without comorbidities (HR = 2.27, 95%CI = 1.48–3.48, p < 0.001). Conclusion: These findings reflect poor healthcare quality, indicating a gap in care for individuals with ASD, particularly those living in socially vulnerable contexts.