IDcare – a longitudinal register study of pre-pandemic and pandemic diagnostic profiles among people with intellectual disabilities: A cohort profile

Background: There are few large register-based studies on people with intellectual disabilities (ID) that compare outcomes with the general population.

Methods: All people in Skåne, the southernmost part of Sweden the 1st of January 2014 was included. Data concerning demographics/vital events, healthcare utilization and service and support for people with ID or autism spectrum disorder (ASD) was collected from registers for 2014-2021. Data on COVID-19 vaccination, palliative care and intensive care were collected from registers for 2020-2021. Those with a registered diagnosis of ID (F7), Down Syndrome (Q90), or with service and support for people with ID or ASD, comprised the ID cohort (n=14716). People living in the same household as someone in the ID cohort were excluded. The remaining comprised the general population cohort (gPop) (n=1226955). The cohorts were also divided into age groups (children: 0-12; adolescents: 13-18; Young adults: 19-24; Adults: 25-44; Lower middle-age:45-54; Upper middle-age:55-64; Older: 65-79; and Oldest old: 80 years and older).

Findings: The ID prevalence was 1.2%. Among those 77.9% had at least one measure of support for people with ID, 63.8% had at least one F7-diagnosis, and 5.8% a Q90 diagnosis. For those with F7-diagnosis 26.9% had mild, 7.4% moderate, 2.8% severe, 1.4% profound, and 25.4 other/unknown ID diagnosis. The proportion of people in the younger age groups were higher in the ID cohort compared to the gPop (children: 24 vs. 14%, adolescents: 14 vs. 6%, young adults: 16 vs. 8%, adults: 27 vs. 26%, lower middle-age: 8 vs. 13%, upper middle-age: 6 vs. 12%, older: 4 vs. 15% and oldest old: 1 vs. 6%).

Conclusions: The prevalence of ID was higher in younger age groups and in mild and other/unknown ID. A large proportion of people with ID had no registered/unknown diagnoses of ID severity during the study period.