Impact of severe skeletal muscle loss during the waiting period on prognosis in lung transplantation for interstitial lung disease.

Objectives: This study aimed to evaluate the impact of skeletal muscle loss during the waiting period on postoperative outcomes following lung transplantation for interstitial lung disease.

Methods: This retrospective analysis included adult patients with interstitial lung disease who underwent deceased- or living-donor lung transplantation at Kyoto University Hospital between 2010 and 2022. Skeletal muscle mass and quality (mean Hounsfield units) of the erector spinae at the 12th thoracic level were quantified using computed tomography. Skeletal muscle loss was defined as a reduction in mass or density while waiting for a transplant. Overall survival and early post-transplant outcomes were compared between patients with skeletal muscle loss and those with preserved muscle.

Results: Of 95 participants, 23 (24.2%) and 72 (75.8%) were classified into skeletal muscle loss and skeletal muscle-maintained groups, respectively. No significant differences were observed in age, sex, or donor types between the two groups. The skeletal muscle loss and maintained groups' median waiting times were 2.1 and 2.3 years, respectively (P = 0.838). Bilateral lung transplantation was more common in the skeletal muscle loss group. Patients with muscle loss had a significantly longer post-transplant hospital stay (77 vs 54 days; P = 0.005) and lower 5-year survival rates (59.5 vs 71.3%; log-rank P = 0.013), respectively. Multivariate Cox regression analysis indicated that skeletal muscle loss was independently associated with poor overall survival (hazard ratio, 2.8; P = 0.004).

Conclusions: Maintaining skeletal muscle during the waiting period is important to improve short- and long-term outcomes after lung transplantation.