Pre-Kidney Transplant Lower Extremity Impairment and Post-Kidney Transplant Mortality

Area of Science:

• Nephrology
• Gerontology
• Rehabilitation Medicine

Background:

• Predicting post-kidney transplantation (KT) mortality remains challenging, with current models exhibiting limited accuracy (C-statistics ≤0.70).
• Objective measures of modifiable factors are needed to enhance prediction and guide interventions for improving KT survival.

Purpose of the Study:

• To evaluate the association between lower extremity function, assessed by the Short Physical Performance Battery (SPPB), and post-kidney transplantation mortality.
• To determine if SPPB scores can serve as an objective, modifiable predictor of KT outcomes.

Main Methods:

• A prospective cohort study of 719 kidney transplant recipients was conducted, assessing SPPB performance and frailty at admission.
• SPPB composite scores (0-12) and impairment (≤10) were analyzed for their independent association with post-KT mortality using adjusted competing risks models, with graft failure as a competing risk.

Main Results:

• Five-year post-transplantation mortality was substantially higher in recipients with SPPB impairment (20.6%) compared to those unimpaired (4.5%, p < 0.001).
• SPPB-impaired recipients faced a 2.30-fold increased risk of post-KT mortality (aHR 2.30, 95% CI 1.12-4.74, p = 0.02).
• Each one-point decrease in SPPB score independently elevated post-KT mortality risk by 1.19-fold (95% CI 1.09-1.30, p < 0.001).

Conclusions:

• Objective assessment of lower extremity function using SPPB is a valuable and modifiable predictor of post-kidney transplantation mortality.
• SPPB offers a promising tool for pre-transplant risk stratification and the development of targeted interventions to improve KT recipient survival.