Low muscle mass in intestinal transplant recipients: Prevalence, outcomes, and longitudinal analysis of body composition

Intestinal transplantation (ITX) is a life-saving treatment for patients with irreversible intestinal failure. While short-term survival has improved, long-term outcomes remain challenging, and the role of Low Muscle Mass (LMM) in influencing post-transplant outcomes is unclear. This study investigates the prevalence and impact of LMM on long-term survival in adults who underwent ITX, while also examining the longitudinal changes in body composition following transplantation.

This retrospective study included 26 adult patients who underwent ITX from February 2000 to August 2023. Body composition was assessed using Dual-Energy X-ray Absorptiometry (DEXA) scans, focusing on appendicular skeletal muscle mass index (ASMI) as an indicator of LMM. Longitudinal changes in ASMI, body fat percentage, body mass index (BMI), and bone mineral density (BMD) were analyzed using mixed linear regression models. Survival analysis was conducted using Kaplan-Meier curves and Cox proportional hazards regression.

Pre-transplant LMM was prevalent in 58 % of patients. Patients with LMM were younger (34 years vs. 49 years, p = 0.001), with lower BMI (18.8 vs. 23.4, p = 0.003) and ASMI (5.1 vs. 6.8, p = 0.0003). Over up to 10 years of follow-up, average ASMI change was 0.02 kg/m²/year (-0.06, 0.10), showing positive time trends in patients younger than 40 years and negative trends in older patients (interaction p = 0.04). A similar age dependence was seen for BMD (interaction p = 0.01). ASMI, BMI, and fat percentage increased from pre-TX to the most recent follow-up, but these changes were not significantly different from zero. Additionally, 5-year mortality and overall survival rates did not significantly differ by pre-TX LMM status.

Pre-TX LMM is common in ITX patients but does not significantly impact long-term survival or body composition post-transplant. Thus, LMM alone may not be a contraindication for ITX, and muscle mass remained relatively stable over the follow-up period.