PROJECT SUMMARY/ABSTRACT Persons with end-stage kidney disease are 16 times more likely to undergo surgery and have significantly increased perioperative risk of mortality, myocardial infarction, and stroke compared to surgical patients with normal or near normal kidney function. Despite this elevated surgical volume and risk profile, little is known about how to best perform preoperative hemodialysis when these patients undergo surgical procedures. The goal of this project is to improve perioperative health for this high-risk surgical population through optimizing preoperative hemodialysis treatment. In Aims 1 and 2, we will evaluate the link between modifiable preoperative dialysis parameters and postoperative complications underlying adverse outcomes. In Aim 3, we will conduct a pilot randomized trial of a novel intervention to control preoperative hemodialysis timing. Accomplishing these goals will help clinicians and policy makers identify optimal dialysis practices for patients with end-stage kidney disease who need surgery. It will also lay the groundwork for future prospective randomized clinical trials of interventions to reduce perioperative mortality and morbidity for these patients. It is innovative in its use of a unique database linking Medicare claims to electronic health records of a major dialysis provider, application of sophisticated statistical methods, and the creation of a multidisciplinary team with clinicians and researchers from multiple disciplines. In addition to the research objectives outlined above, this K23 proposal aims to provide Dr. Vikram Fielding-Singh, MD, JD, with the protected time, training, and research experience to enable him to become an independent clinical investigator focused on perioperative optimization of persons with end-stage kidney disease. Specifically, the proposal will aid Dr. Fielding-Singh’s development through providing support for completion of a Master of Science in Epidemiology and Clinical Research at Stanford University and mentorship by a diverse team of nephrologists, surgeons, and health services researchers. With this training and experience, the candidate will be uniquely positioned to seek further funding to evaluate additional approaches to improve the perioperative health of patients with end-stage kidney disease.