Aging individuals with Down syndrome (DS) are at increased risk of dementia due to trisomy of chromosome 21 on which the amyloid precursor protein gene is located and with increased life expectancy. Yet, little is known about the costs associated with DS dementia and how this compares to Alzheimer's disease (AD).

To better understand direct healthcare costs and care consumption in DS dementia, we compared the total cost of care to US Medicare and the drivers of these medical expenditures in individuals with DS with and without dementia, and in those with AD without DS.

The effect of dementia in DS on costs and care utilization was estimated with 2015 California Medicare fee-for-service data (parts A and B). Among 3,001,977 Californian Medicare beneficiaries, 353 individuals had DS with dementia (age 45–89 years). We compared their number of chronic comorbidity conditions among 27 and their care and Medicare costs to those of age- and sex-matched individuals with DS without dementia and those with AD without DS.

Medicare annual cost per beneficiary was a mean of 43.5% and 82.2% higher with DS dementia (mean $35,011) than DS without dementia (mean $24,401) and AD without dementia (mean $19,212), related to greater utilization of inpatient services. DS dementia was associated with increased level of multimorbidity (mean of 3.4 conditions in addition to dementia vs. 2.7 and 2.2 conditions for DS without dementia and AD, respectively), with more emergency room visits (88% vs. 76.5% and 54.4%) and with more primary care physician visits (91.2% vs. 87.3% and 81.3%).

DS adults with dementia have higher health care costs than DS adults without dementia and adults with AD. Understanding costs and complex health care needs in DS dementia could facilitate management of adult and geriatric care resources for these high-need high-cost individuals.