PROJECT ABSTRACT Adults with Down syndrome (DS) are at increased risk of morbidities5, 6 e.g., almost all develop Alzheimer’s disease by age 60.7 It is critical to improve understanding of health and aging in DS so adults with DS thrive.8 For individuals with DS to reach their fullest potential, we need to quantify and ameliorate impacts of health disparity by predicting then preventing morbidity and mortality. We are making major strides in quantifying the public health impacts and disparities faced by the DS population through our Down Syndrome Toward Optimal Trajectories and Health Equity using Medicaid Analytic eXtract project (DS-TO-THE-MAX; 1R01AG073179- 01 PI: Rubenstein). We developed the largest longitudinal cohort of adults with DS (N=55,000) and have data on all claims and encounters within the Medicaid and Medicare systems from 2011-2019. With such data, we are comprehensively describing the health and health care needs of adults with DS in the US. Yet we are in position to incorporate additional data into DS-TO-THE-MAX that place results in socio-ecologic context and help us identify community and societal level predictors of poor health. Interpersonally, adults with DS often do not receive health care from providers familiar with DS. There are only 14 DS specialty clinics that serve ~3% of adults with DS in the US and many providers have never had a patient with DS. At the community level, neighborhoods affect everyone’s health and adults with DS may be particularly vulnerable to neighborhood deprivation. Medicaid Home and Community Based Service waivers (HCBS) provide services (e.g., transportation) that enable disabled people to thrive in their communities;24 funding, services allowed, and availability of HCBS differ by states and has not been assessed for DS. Therefore, we propose to supplement the individual level DS-TO-THE-MAX claims and encounters data with interpersonal and community level data. Our aims are to 1a) Characterize the type, classification, and specialty of health care providers; and geographic distance needed to travel for adults with DS to care. Then, evaluate differences by state, race / ethnicity, and year 1b) Evaluate whether DS specialty clinics impact dementia incidence and mortality; and 2a): Determine the impact of neighborhood deprivation and other community-level health indicators on health care utilization and on dementia incidence and mortality 2b): Assess HCBS waiver receipt among adults with DS and determine if receipt and generosity of HCBS waivers improves access to care and reduces or delays in dementia incidence and mortality. Our proposal meets the NIH’s call under the INCLUDE project, NOT-OD-20- 024, and PA-20-272 for ‘Cohort Stud[ies] to connect existing resources and expand to inclusion of individuals with Down Syndrome.’ These additional data will bolster DS-TO-THE-MAX and increase impact by spurring community and policy level changes, ultimately, improving health for individuals and the population with DS.

PROJECT NARRATIVE We are making major strides in quantifying the public health impacts and disparities faced by the DS population through our Down Syndrome Toward Optimal Trajectories and Health Equity using Medicaid Analytic eXtract IDS-TO-THE-MAX) project; yet we are in position to incorporate additional data into DS-TO- THE-MAX that place results in socio-ecologic context and help us identify community and societal level predictors of poor health. We propose to supplement the individual level DS-TO-THE-MAX claims and encounters data with interpersonal and community level data to describe and examine the impact of specialty care, distance to care, neighborhood characteristics, and Medicaid waivers on health outcomes (dementia and mortality) for adults with Down syndrome.