Changes in Functional Status Among Kidney Transplant Recipients: Data From the Scientific Registry of Transplant Recipients.

BACKGROUND With stressors of dialysis pre-KT and restoration of kidney function post-KT, it is likely that KT recipients experience a decline in functional status while on the waitlist and improvements post-KT. METHODS We leveraged 224,832 KT recipients from the national registry (SRTR, 2/1990-5/2019) with measured Karnofsky Performance Status (KPS, 0-100%) at listing, KT admission, and post-KT. We quantified the change in KPS from listing to KT using generalized linear models. We described post-KT KPS trajectories using adjusted mixed effects models and tested whether those trajectories differed by age, sex, race, and diabetes status using a Wald test among all KT recipients. We then quantified risk adverse post-KT outcomes (mortality and all-cause graft loss (ACGL)) by preoperative KPS and time-varying KPS. RESULTS Mean KPS declined from listing (83.7%) to admission (78.9%) (mean=4.76%, 95%CI:-4.82,-4.70). After adjustment, mean KPS improved post-KT (slope=0.89%/year, 95%CI:0.87,0.91); younger, female, non-Black, and diabetic recipients experienced greater post-KT improvements (pinteractions<0.001). Lower KPS (per 10% decrease) at admission was associated with greater mortality (aHR=1.11, 95%CI:1.10,1.11) and ACGL (aHR=1.08, 95%CI:1.08,1.09) risk. Lower post-KT KPS (per 10% decrease; time-varying) were more strongly associated with mortality (aHR=1.93, 95%CI:1.92,1.94) and ACGL (aHR=1.84, v95%CI:1.83,1.85). CONCLUSIONS Functional status declines pre-KT and improves post-KT in the national registry. Despite post-KT improvements, poorer functional status at KT and post-KT are associated with greater mortality and ACGL risk. Due to its dynamic nature, clinicians should repeatedly screen for lower functional status pre-KT to refer vulnerable patients to prehabilitation in hopes of reducing risk of adverse post-KT outcomes.