In findings that could place another group onto the COVID at-risk list, researchers in the United Kingdom estimated in a research letter published yesterday that adults with Down syndrome are at almost five times the risk for COVID-19–related hospitalization and 10 times the risk for related death.
The study, published in the Annals of Internal Medicine and led by researchers from the University of Oxford, involved 8.26 million adults, 4,053 of them diagnosed as having Down syndrome. The team analyzed information from a primary care database to determine if the abnormal immune responses, congenital heart disease, and lung abnormalities common in people who have the syndrome could be risk factors for severe COVID-19 illness.
From Jan 24 to Jun 30, 68 of 4,053 patients with Down syndrome died, 27 (39.7%) of them from coronavirus, 17 (25.0%) from pneumonia or pneumonitis (inflammation of lung tissue), and 24 (35.3%) of other causes. In contrast, 41,685 of the 8,252,105 patients without Down syndrome died, 8,457 (20.3%) from COVID-19, 5,999 (14.4%) of pneumonia or pneumonitis, and 27,229 (65.3%) of other causes.
After adjusting for age and sex, the hazard ratio (HR) for coronavirus-related deaths in adults with Down syndrome, versus those without, was 24.94. And after adjusting for age, sex, ethnicity, body mass index (BMI), residency in a long-term care facility, dementia or congenital heart disease, and other underlying conditions and treatments, the HR for COVID-19–associated death was 10.39, and the HR for hospitalization was 4.94.
Much lower risk in those with other learning disabilities
The researchers found no sign of interactions between Down syndrome and age, sex, or BMI, and the HR for death did not change with further adjustment for smoking status and alcohol intake (HR, 10.12). The adjusted HR for people with learning disabilities other than Down syndrome was 1.27.
The authors noted that Down syndrome is not on the US Centers for Disease Control and Prevention list or a similar one maintained in the United Kingdom of conditions that increase the risk of severe coronavirus disease.
The authors said that public health organizations, policymakers, and healthcare professionals should use the study findings to strategically protect people who are especially vulnerable to COVID-19 because of Down syndrome or other conditions.
"These estimated adjusted associations do not have a direct causal interpretation because some adjusted variables may lie on causal pathways, but they can inform policy and motivate further investigation," they wrote. "Participation in day care programs or immunologic deficits could be implicated, for example."