PROJECT SUMMARY/ABSTRACT The HCSRN-OAICs AGING Initiative seeks an Alzheimer’s-focused administrative supplement (NOT-AG-21- 018) to R33 AG057806 to partner with Harvard Pilgrim Health Care Institute to address the following overarching goal: to develop a “shovel-ready” master protocol with detailed analytic approaches that can be executed efficiently on administrative claims data to address the following questions: (1) Among those who are prescribed aducanumab, is use limited to indications specified in the label?; (2) What are the characteristics of patients prescribed aducanumab and what can be ascertained about equity and inclusion in relation to early use of this therapy?; (3) How often are patients prescribed aducanumab who have potential contraindications to therapy, such as being on anticoagulants in view of the risk of brain microhemorrhages?; (4) What diagnostic testing precedes initiation of therapy (e.g., MRI, PET scan, lumbar puncture)?; (5) What are the patterns of monitoring with imaging subsequent to initiation of aducanumab?; (6) How frequently do patients discontinue treatment and at what point after initiation?; (7) What health outcomes are most meaningful to patients and their care partners (recognizing that aducanumab is prescribed to make things “less worse” and not better)?; and (8) Do patients or their care partners perceive a change in clinical course following initiation of aducanumab? The “Advancing Geriatrics Infrastructure and Network Growth” (AGING) Initiative brings together the Health Care Systems Research Network (HCSRN) and the OAICs to advance an interdisciplinary research agenda focused on older adults with multiple chronic conditions (MCCs). The specific aims under the AGING Initiative R33 are: (1) to expand on and further develop innovative methods related to measurement and analytics, observational research, and pragmatic clinical trial design and implementation, to inform the development and testing of novel interventions that improve the care and outcomes of older persons with MCCs; (2) to foster the career development and success of new and early-stage investigators, including underrepresented minorities; (3) to create a new core function as part of an elaborated infrastructure that promotes patient-centered research by engaging patients and care partners in all stages of the research process; and (4) to fund a series of “P-2-R” (“Pilot-to-R award”) grants. The proposed project will expand the toolbox of methodologic approaches and data resources that can be applied to the portfolio of research conducted under and fostered by the R33. The expectation is that the efforts undertaken through this supplement will be applicable to other novel therapies for Alzheimer’s disease that may receive FDA approval over the coming months and years and will lay the groundwork for a future comparative effectiveness study which emulates a randomized controlled trial.