PROJECT SUMMARY/ABSTRACT Alzheimer's disease and related dementias (AD/dementia) represent a looming public health crisis, affecting roughly 5 million people in the U.S. and 11% of older adults. As with other chronic conditions, racial/ethnic and socio-economic disparities exist in the prevalence and burden of illness. However, less is known about how disparities in access to care influence the care trajectories ? i.e. the scope, frequency and sequence of services used across health care settings ? of those with AD/dementia. This retrospective, longitudinal cohort study will address this gap by using network analysis to examine care trajectories and outcomes in a racially and socioeconomically diverse sample of community-dwelling individuals with AD/dementia and unspecified cognitive impairment (CI) who may be at risk for a delayed AD/dementia diagnosis. The cohort will consist of home health care patients served by the Visiting Nurse Service of New York (VNSNY), a large, non-profit home care provider. Data will include clinical assessments for roughly 89,000 patients admitted to home care during 2010-2012 linked with 4 years of Medicare and Medicaid claims data and geographic data on neighborhood services. The specific aims are to: (1) Describe the population at VNSNY within two diagnostic categories (AD/dementia and unspecified CI) in relation to adverse outcomes (e.g. pressure ulcers, falls, infection, dehydration, preventable hospitalization, and nursing home admission); (2) Map, quantify and compare patterns in the care trajectories of individuals and groups that experience variable and/or disparate outcomes; and (3) Identify strategies for implementing care trajectories with potential to reduce disparities in access and/or outcomes for AD/dementia and unspecified CI. Applying a systems science framework, the study will use innovative network analytics to capture complex patterns in care trajectories that may contribute to adverse outcomes in a racially and socioeconomically diverse sample of individuals with these two conditions. The long-term goal of this research is to identify and, in subsequent studies, test potential home- and community-based interventions that may improve access to services and outcomes for individuals who may be underserved or at heightened risk for unmet healthcare needs. This research will produce new knowledge to aid efforts to mitigate health disparities in this vulnerable and growing population.