Immediate and Underlying Causes of Death and Survival Rates in Aging Adults With Down Syndrome

BACKGROUND: To describe immediate and underlying causes of mortality (using ICD-10 codes) and survival rates of aging adults with Down syndrome (Ds). METHOD: This secondary analysis used the Healthy Aging and Intellectual Disabilities cohort. Adults with Ds (n = 149, ≥ 50 years at baseline) were matched 1:1 to adults with intellectual disabilities without Ds on age, sex and level of intellectual disability. Follow-up was ~10 years post-baseline, or at death. RESULTS: The most common immediate and underlying causes of death in adults with Ds were respiratory diseases/infections, followed by cardiovascular disease and neuropsychiatric conditions. Unknown causes accounted for 29%-50% of deaths. Adults with Ds had higher mortality than matched comparators (HR = 5.05, 95% CI 3.10-7.47), increasing significantly with each year of age (HR = 1.08/year, 95% CI 1.04-1.11). CONCLUSION: Respiratory diseases, cardiovascular and neuropsychiatric conditions are important contributors to mortality in older adults with Ds, but large numbers of missing causes warrant cautious interpretation.