Study: Mortality in people with intellectual disabilities extended beyond deaths from COVID itself

New research presented at this year's European Congress of Clinical Microbiology & Infectious Diseases (Copenhagen, April 15–18) and published in The Lancet Public Health shows that the impact of COVID-19 on mortality in people living with intellectual disabilities extended beyond deaths from the virus itself, and was linked with increased mortality in several other conditions. The study is by Dr. Maarten Cuypers, Radboud University Medical Center, Nijmegen, the Netherlands, and colleagues.

Although high rates of COVID-19-related deaths have been reported for people with intellectual disabilities during the first two years of the pandemic, it is unknown to what extent the pandemic has impacted existing mortality disparities for people with intellectual disabilities.

This population-based cohort study used a pre-existing cohort that included the entire Dutch adult population (everyone aged ≥18 years) on Jan 1, 2015, and identified people with presumed intellectual disabilities through data linkage. For all individuals within the cohort who died up to and including Dec 31, 2021, mortality data were obtained from the Dutch mortality register.

Therefore, for each individual in the cohort, information was available about demographics (sex and date of birth), indicators of intellectual disability, if any, based on chronic care and (social) services use, and in case of death, the date and underlying cause of death. The authors compared the first two years of the COVID-19 pandemic (2020 and 2021) with the pre-pandemic period (2015–19). The primary outcomes in this study were all-cause and cause-specific mortality. They calculated rates of death and generated hazard ratios (HRs) using statistical modeling.

At the start of follow-up in 2015, 187,149 Dutch adults with indicators of intellectual disability were enrolled and 12.6 million adults from the general population were included. Mortality from COVID-19 was five times higher in the population with intellectual disabilities than in the general population, with a particularly large disparity at younger ages (22 times higher below 30 years of age, and still nine times higher below 60 years of age) that declined with increasing age.

The overall mortality from all causes disparity during the COVID-19 pandemic (HR 3.38 times higher) was 5% higher (than before the pandemic (3.23 times higher), This increased overall mortality disparity was not completely explained by the excess risk for people with intellectual disabilities to die from COVID-19, but increasing mortality disparities were also seen for causes related to cancer, mental, behavioral and nervous system disorders, and external causes. Thus, although people with intellectual disabilities were already facing a pre-existing mortality disparity, the magnitude of this risk difference relative to the general population increased during the pandemic.

The authors say, "Our study showed that the full impact of the COVID-19 pandemic has been much greater than indicated by reported deaths due to COVID-19 alone. Existing mortality disparities between people with and without intellectual disabilities have been further widened compared with the period 2015–19."

They conclude, "The health risks for people with intellectual disabilities warrant targeted policy making regarding protective measures for the current pandemic and future pandemic preparedness that go beyond the causative agent of a pandemic alone. This study shows the need for better monitoring of vulnerable populations, such as people with disabilities, who are at risk of otherwise being overlooked, with marked consequences."