*Purpose: Poor physical function in kidney transplant candidates is associated with frailty, sub-optimal transplant outcomes, and higher health care utilization. We need an instrument to objectively assess physical function in patients on the kidney waitlist. Our center began in-person re-evaluations of waitlisted patients with high allocation priority based on the new Kidney Allocation System. We used the 6-minute walk (6MWT) as a measure of cardiorespiratory fitness and 1-minute sit-to-stand tests (STS) as a measure of lower extremity strength. We hypothesize that 6MWT result is strongly correlated with STS result and incorporates information beyond co-morbidities.

*Methods: Nurse coordinators invited waitlisted patients with high allocation priority for evaluation at our Transplant Readiness Assessment Clinic (TRAC). We performed a retrospective chart review and data extraction of patients evaluated in TRAC from May 2017 through August 2018. A generalized estimating equation with clustering to account for multiple tests in the same patient was used to estimate the association between the covariates and 6MWT.

*Results: Over the study period, we evaluated 252 patients (Table 1). Mean 6MWT and STS results were 349±124 meters and 16±8 repetitions, respectively. 6MWT results were normally distributed over the range of common physical activities (Figure 1) and closely correlated with STS results (r=0.66). STS results were not normally distributed. In univariate regression, patient age, sex, dialysis duration, comorbidities, and STS were all associated with 6MWT performance. In multivariate regression, only age (p<0.0097), sex (p=0.0049) and STS result (p=0.005) were independently associated with 6MWT results.

*Conclusions: In waitlisted kidney transplant candidates, 6MWT is normally distributed and associated with lower extremity strength, age and sex but not other comorbidities. These findings suggest that the 6MWT is a promising metric to quantify cardiorespiratory fitness in kidney transplant candidates beyond traditional comorbidities.

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