CT-Derived Body Composition and Perioperative Outcomes in Living Kidney Donors
2Oncology Department, Rabin Medical Center, Israel
3Department of Organ Transplantation, Rabin Medical Center, Israel
Purpose:
To evaluate associations between CT-derived body composition and perioperative and renal outcomes following living kidney donation.
Materials and Methods:
This retrospective study included 703 living kidney donors (424 men, 278 women) who underwent preoperative non-contrast CT. Body composition was automatically analyzed using CompoCT, a CT-based body-composition software developed at the Samueli Institute, which localizes the L3 level and segments skeletal muscle and adipose tissue compartments. Skeletal muscle (−29 to +150 HU) was subdivided into steatotic (−29 to +29 HU) and healthy muscle (+30 to +150 HU). Muscle and adipose tissue areas and height-normalized indices were assessed. Outcomes included operative duration, length of stay (LOS), postoperative and one-year creatinine, and postoperative complications. Associations were evaluated using Spearman`s rank correlation (ρ), with sex-stratified analyses and false discovery rate (FDR)–corrected q-values reported throughout.
Results:
Greater adiposity was associated with longer operative duration, particularly in men; visceral fat area and total fat index showed the strongest correlations (both ρ=0.229, q<0.001). BMI was also associated with operative duration (ρ=0.172, q=0.001).
Higher healthy muscle index (ρ=−0.242), healthy muscle fraction (ρ=−0.239), and healthy muscle area (ρ=−0.226) were associated with shorter LOS, predominantly in women (all q<0.001 pooled); steatotic muscle showed the inverse relationship, also women-driven. Each SD increase in healthy muscle fraction was independently associated with 0.216-day shorter LOS (95% CI, −0.340 to −0.093).
Healthy muscle area, healthy muscle index, and skeletal muscle index were associated with postoperative and one-year creatinine in both sexes, whereas steatotic muscle was not.
CT body composition did not predict discrete postoperative complications.
Conclusion:
CT-derived body composition demonstrates outcome-specific associations: adiposity is associated with operative duration, while muscle quantity and quality are associated with LOS and serum creatinine. This finding raises the possibility that muscle composition, independent of muscle mass, contributes to variability in creatinine-based renal function estimates.