Pre- and Post-Kidney Transplant Abdominal Computed Tomography-Based Muscle Measurements and Post-KT Outcomes.

INTRODUCTION

Early post-kidney transplant (KT) changes likely impact body composition, resulting in adverse post-KT outcomes. We estimated post-KT trajectories of computed tomography (CT)-based muscle quantity/quality and tested whether they were associated with mortality and death-censored graft loss (DCGL) among frail and nonfrail recipients.

METHODS

We leveraged a cohort of 294 adult KT recipients (December 2008-February 2020) with CT measurements (muscle quantity: skeletal muscle index; muscle quality: skeletal muscle radiation attenuation). We used mixed linear regression models to estimate 3-year post-KT muscle quantity/quality trajectories. Cox proportional hazard models quantified the association between time-varying pre-/post-KT muscle mass measurements and post-KT mortality and DCGL.

RESULTS

Muscle quantity (-2.4 cm2/m2/year) and quality (-1.3 HU/year) decreased during the first 2 years post-KT and then remained constant in the third year post-KT. Change in muscle quantity (pinteraction < 0.01) and quality (pinteraction = 0.01) differed by frailty in the first 2 years post-KT; change in muscle quality (pinteraction < 0.01) differed by lower extremity impairment in the third year post-KT. Among frail recipients, lower muscle quantity (per 10 cm2/m2) was associated with elevated mortality risk (aHR: 2.00, 95% CI: 1.08-3.70), but not among nonfrail recipients. Among older (≥65 years) recipients, lower muscle quantity was associated with increased DCGL risk (aHR: 2.70, 95% CI: 1.04-7.04), but not among younger recipients. Lower muscle quality (per 10 HU) was associated with elevated mortality (aHR: 2.23, 95% CI: 1.61-3.08) and DCGL (aHR: 1.90, 95% CI: 1.16-3.12) risk.

CONCLUSION

Lower pre-/post-KT muscle quantity/quality were associated with higher risks of post-KT adverse outcomes. Pre-/post-KT rehabilitation to improve muscle quantity/quality may be an effective clinical intervention to minimize risks of adverse post-KT outcomes.