Avoidable mortality, clinical outcomes and determinants of premature death among adults with severe or profound intellectual disability: A population-based analysis of mortality data in England

Background: Adults with intellectual disabilities experience significantly worse health outcomes and die younger than people without intellectual disability. People with severe or profound intellectual disability have particularly complex health needs. However, no large-scale population-based studies have specifically examined mortality patterns and factors associated with age at death in this group. Methods and findings: This population-based study used data from the English Learning from Lives and Deaths (LeDeR) mortality review programme and the Office for National Statistics (ONS) between 2021 and 2023. We included 1,301 adults with severe or profound intellectual disability, 2,626 adults with mild or moderate intellectual disability, and 536,311 adults from the general population. We collected sociodemographic, clinical, and mortality data. Key outcomes included co-occurring conditions, age at death, causes of death, avoidable mortality, and years of life lost. We used Cox regression and multiple linear regression to examine factors associated with age at death. We defined avoidable deaths as deaths before the age of 75 years due to preventable or treatable causes and adjudicated them by mapping the underlying cause of death to the Organisation for Economic Co-operation and Development (OECD) list of avoidable causes of death. Adults with severe or profound intellectual disability had a significantly higher prevalence of dysphagia (63.0%), epilepsy (36.1%) and visual problems (35.9%) compared with those with mild or moderate intellectual disability (p