Prognostic impact of low muscle mass on clinical outcomes in lung transplant patients.

Background: Low muscle mass (LMM) is recognized as a poor prognostic factor in various chronic lung diseases. However, its prognostic impact on lung transplant recipients remains inconclusive.

Methods: We retrospectively analyzed patients who underwent lung transplantation at a tertiary referral center in South Korea. Pre-transplant skeletal muscle mass was quantified at the L1 vertebral level by chest computed tomography scans using a commercially available body composition analysis software. Patients were classified into LMM and non-LMM group using a threshold for LMM that had been previously validated in the South Korean population. We then evaluated the prognostic impact of preoperative LMM on clinical outcomes after lung transplantation.

Results: A total of 107 patients were included in this analysis, of whom 44 (41.1%) were classified into the LMM group. The median follow-up duration was 958 days post-transplantation. A preoperative LMM was identified as an independent factor associated with a higher risk of overall mortality (adjusted HR 2.15, 95% CI 1.07-4.34). Additionally, patients with LMM had a higher risk of developing primary graft dysfunction (adjusted OR 3.56, 95% CI 1.25-10.18). At the 1-year follow-up, 37.5% of the patients with baseline LMM had recovered and were reclassified into the non-LMM group, and this improvement was found to mitigate the negative impact of preoperative LMM.

Conclusions: Pre-transplant LMM was significantly associated with poor clinical outcomes in lung transplant recipients. These findings highlight the importance of maintaining adequate muscle mass during the waiting period for lung transplantation.