COVID-19's hidden toll: Study reveals greater mortality disparities for people with intellectual disabilities

By Pooja Toshniwal PahariaReviewed by Lily Ramsey, LLMApr 18 2023

In a recent study published in The Lancet Public Health journal researchers analyzed cause-specific and any-cause mortality among individuals with or without intellectual-type disabilities before and during coronavirus disease 2019 (COVID-19).

Intellectually disabled individuals usually have disparities in health due to barriers to accessing healthcare services or immunodeficiencies, which lead to worse disease outcomes and early death. Increased COVID-19-associated mortality has been documented among the disabled population between 2020 and 2021. However, information on the magnitude of the impact on death disparities for disabled individuals is limited.

Study: All-cause and cause-specific mortality among people with and without intellectual disabilities during the COVID-19 pandemic in the Netherlands: a population-based cohort study. Image Credit: next143 / Shutterstock

About the study

In the present study, researchers investigated whether there was an increase in cause-particular and any-cause mortality among individuals with intellectual disabilities during the COVID-19 pandemic.

The team linked the adult Dutch population with the death registry of the Netherlands, comprising data on the demographics (age and sex), intellectual status based on the utilization of social services and chronic care services, and the cause and date of death for individuals who were deceased by December 31, 2021.

The findings during COVID-19 (January 1, 2020, and December 31, 2021) were compared with those before COVID-19 (between January 1, 2015, and December 31, 2019). The primary study outcomes were cause-particular and all-cause mortality. Cox regression modeling was performed to calculate the mortality rates and hazard ratio (HR) values.

COVID-19-associated mortality was based on the International Classification of Diseases and Related Health Problems, tenth revision (ICD-10) codes. Mortality rates were calculated among every 10,000 individuals/year. In addition, the PubMed database was searched for English records published between the inception of the database and August 11, 2022.

Results

In 2015, 187,149 adult Dutch residents with intellectual disability indicators and 13 million adults representing the general public were recruited. The disabled population comprised 57% (n=107,370) of males and was younger compared to the general public (mean age, 40 years versus 48 years). Between 2015 and 2021, 1,057,163 and 16,528 deaths among the general and disabled populations, respectively, were documented in the death register.

In the pre-pandemic period, crude death rates among disabled adults (per 10,000 individuals/year) ranged from 110 to 132, and among the general public, they ranged from 114 to 120. In the pandemic period, the corresponding crude mortality rates ranged from 144 to 158, and from 133 to 136, respectively. Between 2020 and 2021, COVID-19 was the cause of death for 765 disabled adults and 166 to 178 non-disabled individuals. COVID-19-associated mortality was significantly greater among the intellectually disabled population compared to the general public (HR 4.9), with an especially large discrepancy at lower ages that reduced with advancing age.

On the whole, the disparity in mortality in the pandemic period (HR 3.4) was wider compared to that before COVID-19 (HR 3.2). Concerning disease groups such as behavioral, mental, and nervous system-associated causes; neoplasm-associated causes; non-natural or external causes; circulatory system-associated reasons; and natural or other causes), the mortality rate was more significant for intellectually disabled adults during COVID-19 compared to the pre-COVID-19 period.

The disparity in death rates between the two periods was greater among the disabled population compared to the general public, even though the relative death risks for the majority of other causes were within comparable ranges to the pre-COVID-19 years. The relative risk for COVID-19-associated deaths was more significant for disabled women (HR 6.2) compared to disabled men (HR 4.3). The disabled population died earlier (68 years) due to COVID-19 compared to the general population (82 years).

Noteworthy changes in the reasons for death among disabled adults included a rise in deaths from poorly defined neoplasms, fewer pneumonia-associated deaths, more deaths due to accidental falls, an increase in diabetes-associated deaths, and a decrease in deaths due to Down syndrome. An increase in deaths was reported due to unspecified reasons during COVID-19 compared to the pre-COVID-19 period. The data search yielded 76 records, of which 22 documented primary information on deaths from COVID-19.

Most studies analyzed data from the initial COVID-19 waves only, and only six records included data from the beginning of the pandemic through the initial months of 2021. Four records reported any-cause mortality, and the other studies examined COVID-19 case fatalities for identifying risk factors; however, none assessed cause-specific deaths due to non-COVID-19 reasons. The records indicated a greater mortality risk for disabled individuals, especially for Down syndrome patients and those residing in congregate-type settings. Studies addressing excessive deaths due to COVID-19 reported a positive association between the pandemic and intellectual-type disabilities.

Conclusions

Overall, the study findings showed that COVID-19 impacted intellectually disabled Dutch adults more severely than that indicated by documented COVID-19-associated deaths alone. The risk of COVID-19-associated death was more significant in the disabled population compared to the general public, and the overall disparities in mortality were further aggravated in the initial two years of COVID-19.

The health-associated risks for disabled adults warrant tailored policy formulation and decision-making concerning protective health measures to improve global preparedness for COVID-19 and future pandemics. The findings highlight the need for better monitoring at-risk individuals, including those with intellectual-type disabilities, who may be overlooked, with adverse consequences.