PROJECT SUMMARY Ableist discrimination is pervasive in healthcare and negatively affects the US organ transplant system, resulting in patients with intellectual or developmental disabilities (IDD) often being unjustly excluded from life-saving transplantation. To address this inequity, thirty-nine states have passed laws prohibiting disability-based discrimination in organ transplantation. Currently, we do not know the extent to which anti-discrimination laws mitigate ableism against patients with IDD, nor do we know which patient factors compound with ableism to exacerbate disparities in transplantation access. Focusing on kidney transplantation, the most commonly transplanted solid organ in the US, we will leverage our team’s unique expertise in IDD, transplant equity, population-level claims data, and policy evaluation to achieve our specific aims: (Aim 1) determine the efficacy of state laws prohibiting ableist discrimination in closing the equity gap between kidney transplant candidates with vs. without IDD; (Aim 2) identify patient factors that compound with ableism to disproportionately reduce kidney transplant access and increase dialysis time for patients with vs. without IDD; (Exploratory Aim 3) compare reasons for exclusion among patients with vs. without IDD to understand how ableism impacts access to kidney transplantation. We will achieve these aims through the synergistic use of national Medicare claims data and local electronic health records (EHR) data. In Aim 1, we will use staggered adoption difference-in- difference models to assess the impact of anti-discrimination laws on kidney transplant access for propensity score matched samples of patients with and without IDD. In Aim 2, we will use multi-level regression and time- to-event models with interaction terms and contrast statements to quantify the compounding effects of comorbidities and social determinants of health with ableism for patients with IDD relative to propensity-score matched patients without IDD. Last, in Exploratory Aim 3, we will leverage EHR data from four large academic transplant centers to compare the stated reasons for kidney transplant denial between patients with and without IDD. Findings will have practical applications for healthcare providers, regulatory agencies, and legislators responsible for mitigating ableism against people with IDD in organ transplantation. This study is responsive to RFA-HD-24-007 in that we will “examine the impact of existing efforts to address ableism (e.g., laws) on the health of individuals” with IDD and how patient factors mediate the “impacts of ableism on health.” This project will have a high public health impact yielding new, actionable information to further mitigate ableism against people with IDD in organ transplantation and improve equitable access to this life-saving care.