Skeletal Muscle Index as a Prognostic Marker for Kidney Transplantation in Older Patients

Objective: Low skeletal muscle mass has emerged as a risk factor for mortality after liver transplantation. We evaluated the prognostic value of muscle mass on length of hospitalization and adverse outcomes after kidney transplantation in aging end-stage renal disease patients.

Methods: One hundred twenty-two patients aged 60 years or older at the time of transplantation were retrospectively analyzed. Skeletal muscle index (SMI), evaluated by computed tomography scan, was calculated from total muscle surface area at L3 vertebral level divided by body height squared. Outcomes were compared according to SMI (namely, length of hospitalization, wound complications, combined endpoint comprising all-cause mortality, and graft failure within 1 year).

Results: In male patients, by multivariate analysis, a low SMI (<42 cm²/m²) was associated with longer immediate post-transplantation hospitalization (β = 17.03 ± 4.3; P = .0002), longer total hospitalization during the first year (β = 34.3 ± 10.7; P = .002), higher rate of wound complications (odds ratio = 12.1 [1.9-77.0]; P = .008), and higher rate of the combined endpoint of graft loss or death (odds ratio = 3.4 [3.0-399.5]; P = .004). In female patients, low SMI was not associated with length of hospitalization or adverse outcomes after transplantation.

Conclusion: SMI is an independent marker of morbidity and mortality after kidney transplantation in older men and could help thereby nephrologists better select aging candidates for kidney transplantation with a view to improving post-transplant outcomes.