PROJECT SUMMARY AND ABSTRACT Many patients with Alzheimer’s Disease and Related Dementias (ADRD) undergo surgery. Indeed, patients with ADRD patients account for 25% of patients undergoing hip fracture surgery and 10% of patients undergoing high risk surgery. However, the extent to which these patients are at higher risk for adverse postoperative outcomes remains unknown, with existing studies finding conflicting results. Moreover, while many aspects of the management of these patients, such as the use of certain anesthetic agents and gases, have been hypothesized to improve or worsen postoperative outcomes, the evidence base in support of these hypotheses is weak. Our long-term goal is to advance the health of surgical patients with ADRD by developing individualized models of risk assessment as well as evidence-based guidelines aimed at reducing this risk. Towards this end, the overall objective of this study is to (a) identify the extent to which surgical patients with ADRD are at increased risk for adverse postoperative outcomes and (b) estimate the association between various perioperative interventions (e.g., use of anesthetic gases, choice of discharge location) and the incidence of adverse postoperative outcomes. Specifically, this study will test the central hypothesis that surgical patients with ADRD are at increased risk for adverse postoperative outcomes but that appropriate perioperative interventions can reduce this risk. To assess this hypothesis, this study will use a novel linkage between two datasets: healthcare claims data and the Multicenter Perioperative Outcomes Group (MPOG), a large, multicenter registry of surgical cases using data extracted from electronic medical records. This linkage will produce a unique dataset that unites the best aspects of both datasets: the ability to measure perioperative care and the ability to follow patients over time to assess outcomes. We will accomplish the project goals through three specific aims. First, using healthcare claims data, we will evaluate the extent to which patients with ADRD are at increased risk for worse postoperative outcomes and identify the factors that mediate this risk. Second, using the linked healthcare claims data-MPOG dataset, we will evaluate the association between perioperative interventions (e.g., use of anesthetic gases, choice of discharge location) and the incidence of adverse short-term outcomes. Finally, using the linked healthcare claims data-MPOG dataset, we will evaluate the association between perioperative interventions and the incidence of adverse medium and long-term surgical outcomes. The completion of this project will result in a comprehensive understanding of the risks facing surgical patients with ADRD as well as the interventions that can reduce this risk. In addition, it will also help identify targets for further study through randomized trials, and influence clinical guidelines and policies aimed at improving population health outcomes amon...