Prevalence of physical conditions and multimorbidity in a cohort of adults with intellectual disabilities with and without Down syndrome: cross-sectional study.

Objectives: To investigate the prevalence of multimorbidity in adults with intellectual disabilities with and without Down syndrome.

Design: Large, population-based cross-sectional study.

Setting: The geographical area of one Health Board, Scotland.

Participants: All adults (aged 16+ years) known to general practitioners to have intellectual disabilities and adults receiving services provided or paid by intellectual disabilities health or social work services. 1023/1562 potential participants took part (65.5%); 562 (54.9%) men and 461 (45.1%) women, aged 43.9 years (16-83 years). 186 had Down syndrome and 837 did not.

Main Outcome Measures: The prevalence of International Statistical Classification of Diseases, 10th revision, physical health conditions and multimorbidity detected at a comprehensive health assessment.

Results: The mean number of physical health conditions/participant was 11.04, and 98.7% had multimorbidity. The most prevalent conditions are painful and/or disabling and, in some cases, life threatening. The five most prevalent were visual impairment, obesity, epilepsy, constipation and ataxic/gait disorders. The pattern of multimorbidity differs from that seen in the general population and is spread across the entire adult life course. The extent of multimorbidity in the adults with Down syndrome was similar to that of the adults without Down syndrome, while the prevalence of individual conditions differed.

Conclusions: This robustly designed study with a large population found an extremely high prevalence of multimorbidity in adults with intellectual disabilities across the entire adult life course. This increases complexity of medical management that secondary healthcare services and medical education are not yet geared towards, as these tend to focus on single conditions. This is in addition to complexity due to limitations in communication and understanding. As the physical conditions within their multimorbidity also differ from that seen in the older general population, urgent attention is needed to develop the care pathways and guidelines that are required to inform and so improve their healthcare.