Scottish cohort of 3.7 million adults links disability and household setting to COVID-19

IntroductionDisabled people experienced a disproportionate burden of COVID-19, yet evidence on how household living arrangements shaped these outcomes across disability groups remains limited.

ObjectiveTo describe the creation, content, and baseline characteristics of a population-based linked administrative cohort for studying disability, residential context, and COVID-19 infection, hospitalisation, and mortality in Scotland.

MethodsThe cohort was assembled from Community Health Index records for people alive and resident in Scotland on 1 March 2020 whose residential addresses could be linked to Unique Property Reference Numbers. Records for those aged under 16 years at that date were excluded, and the remainder were linked to the 2011 Scottish Census to obtain disability status and sociodemographic characteristics. Disability was classified sequentially into three mutually exclusive groups: intellectual disability, including individuals who may also have reported physical or sensory disability; physical disability, including sensory impairments but excluding intellectual disability; and a comparison group without reported intellectual or physical disability. Household context was characterised by residential setting and household size. Residential setting was classified from Basic Land and Property Unit codes as private dwellings, small communal establishments (fewer than 50 linked residents), or large communal establishments (50 or more linked residents). Household size was grouped as 1, 2--4, 5--7, 8--10, or 11 or more linked residents. Laboratory-confirmed SARS-CoV-2 infection and COVID-19-related hospitalisation and mortality were ascertained from national surveillance and administrative records between 1 March 2020 and 30 April 2022. Age- and sex-adjusted incidence rates were estimated using Poisson regression with log person-time as an offset.

ResultsOf 4,132,960 age-eligible Community Health Index records, 3,719,651 adults (90.0%) were successfully linked to the Census and included in the cohort. Of these, 17,354 had intellectual disability, 377,706 had physical disability and 3,324,591 were in the comparison group. During follow-up, 306,343 cohort members had a laboratory-confirmed SARS-CoV-2 infection, 22,945 were hospitalised with COVID-19 and 12,893 died from COVID-19-related causes. The corresponding crude incidence rates were 592 infections, 32 hospitalisations and 16 deaths per 10,000 person-years. Age- and sex-adjusted rates were highest among adults with intellectual disability, at 1,486 infections, 86 hospitalisations and 56 deaths per 10,000 person-years. The corresponding rates were 932, 58 and 33 among adults with physical disability, and 570, 29 and 12 in the comparison group. Across all three outcomes, adjusted incidence rates were higher in communal establishments than in private dwellings and generally increased with household size. Mortality differences were especially pronounced in communal establishments and at addresses with 11 or more linked residents.

ConclusionsThis population-based, Census-linked cohort integrates information on disability and residential context with national health and administrative records. Although developed to examine COVID-19 outcomes, it provides a broader platform for investigating how disability and living arrangements shape health inequalities in Scotland.