*Purpose: Functional status assessment (FSA) is important to kidney transplant (KT) candidacy evaluation; a low Fried Frailty score (FFS) is associated with poor waitlist and post-transplant outcomes. However, FFS fails to capture physical or cardiopulmonary fitness, which correlate with mortality in cardiac and dialysis populations. We developed a standardized approach to FSA using the 6 Minute Walk Test (6MWT), 30-second sit-to-stand test (30STS) and FFS. Here, we summarize functional status characteristics in our cohort of KT candidates and present early post-transplant outcomes in a subset of patients who completed the 6MWT and 30STS at time of transplant.

*Methods: All patients who completed FSA between 11/2020-10/2021 and had a 6MWT were included in this retrospective analysis. We recorded 90-day outcomes from patients with at least 3 months of post-transplant follow up in a retrospective chart review. Linear regression was used to assess correlations between 6MWT and patient characteristics. Logistic regression was used to assess waitlist outcomes and 6MWT performance.

*Results: 985 patients had complete FSA data for inclusion. On average, patients walked 375 meters (m) on 6MWT, completed 11.8 sit-to-stands, had a mean FFS of 1.1. Increasing age correlated with lower 6MWT distance, dropping 0.02 m (p<0.001) with each year increase. Each year of dialysis decreased distance walked by 2.8 m (p=0.012 adjusted for age, sex, diabetes). Gender, ethnicity, diabetic status, estimated post-Tx survival score, and calculated panel reactive antibody percentage were not significantly correlated with 6MWT distance.

Increasing distance walked on 6MWT by 10 m correlated with increased odds of transplant listing by 10% (p<0.001) and increased odds of continuing evaluation status by 2% (p=0.005). Decreasing distance walked on 6MWT by 10 m correlated with increased odds of case closure by 10% (p<0.001). Mortality was 3.3% in patients who walked <300 m, compared with 2.0% in those who walked >300 m (p=0.28).

133 patients completed 6MWT and 30STS at time of KT and had at least 3 months of post-transplant follow-up time. Total distance walked on 6MWT was not found to be correlated with length of stay, delayed graft function, 30-day or 90-day serum creatinine, 90-day readmissions or ED visits.

*Conclusions: Use of 6MWT, 30STS and FFS are helpful in standardizing patients’ FSAs, though further studies are needed to determine 6MWT cutoffs that identify those at higher risk of poorer waitlist and post-transplant outcomes. While our data does not yet demonstrate significance in waitlist mortality prediction or post-transplant outcomes, the current analysis is limited by time and low number of post-transplant patients.

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