Longitudinal CT-Based Assessment of Muscle and Bone Changes After Liver Transplantation in Hepatitis B Patients with and Without Hepatocellular Carcinoma

Background/Objectives: Sarcopenia and impaired bone quality are increasingly recognized as important determinants of outcomes after liver transplantation (LT). However, longitudinal data describing early post-transplant musculoskeletal changes in patients with chronic hepatitis B virus (HBV) infection, particularly according to hepatocellular carcinoma (HCC) status, remain limited. Aim: To evaluate longitudinal changes in skeletal muscle mass and vertebral bone attenuation after LT in patients with chronic HBV infection and to assess the impact of concomitant HCC and clinical subgroups on these patterns. Methods: This retrospective, single-center study included 99 adult patients who underwent LT for chronic HBV infection (HBV alone, n = 59; HBV + HCC, n = 40) between January 2018 and December 2024. Contrast-enhanced abdominal computed tomography examinations obtained before transplantation and at approximately 6 (POD180) and 12 months (POD365) after transplantation were analyzed. Skeletal muscle was assessed using psoas muscle area (PMA) and psoas muscle index (PMI), while bone quality was evaluated using mean vertebral trabecular attenuation averaged across L1–4. Longitudinal changes were examined according to HCC status, sex, Child–Pugh class, and survival status. Results: Repeated-measures analyses of longitudinal changes demonstrated a significant decline in both PMA and PMI at POD180 and POD365 compared with pre-transplant values (PMA: p = 0.006; PMI: p = 0.009). These patterns were comparable between patients with HBV alone and those with HBV-related HCC, with no significant differences between groups (all p > 0.05). Male patients consistently exhibited higher PMA and PMI values than female patients across all assessed time points (both p < 0.001). In contrast, neither Child–Pugh class nor mortality status was associated with differences in PMA or PMI levels (all p > 0.05). L1–4 attenuation declined markedly by POD180 and remained below baseline at POD365 (p < 0.001). Although overall L1–4 values did not differ between disease groups (p = 0.109), the temporal pattern of L1–4 change differed according to survival status (p = 0.026), with a greater decline observed in non-survivors. Conclusions: In patients with chronic HBV undergoing LT, early post-transplant loss of skeletal muscle and vertebral bone attenuation is common and persists throughout the first year of follow-up. These changes occur similarly in patients with and without HCC. CT-based assessment of muscle and bone parameters, particularly L1–4 attenuation, may therefore support early post-transplant risk stratification.