Evaluation of Skeletal Muscle Function in Lung Transplant Candidates

BACKGROUNDLung transplantation (LTx) is offered to older and more complex patients who may be at higher risk of skeletal muscle dysfunction, but the clinical implications of this remain uncertain. The study aims were to characterize deficits in skeletal muscle mass, strength and physical performance, and examine the associations of these deficits with clinical outcomes. METHODSFifty LTx candidates (58% men; age, 59 ± 9 years) were prospectively evaluated for skeletal muscle deficitsmuscle mass using bioelectrical impedance, quadriceps, respiratory muscle and handgrip strength, and physical performance with the Short Physical Performance Battery. Comparisons between number of muscle deficits (low muscle mass, quadriceps strength and physical performance) and 6-minute walk distance (6MWD), London Chest Activity of Daily Living Questionnaire, and quality of life were assessed using one-way analysis of variance. Associations with pretransplant and posttransplant delisting/mortality, hospital duration, and 3-month posttransplant 6MWD were evaluated using Fisher exact test and Spearman correlation. RESULTSDeficits in quadriceps strength (n = 27) and physical performance (n = 24) were more common than muscle mass (n = 8). LTx candidates with 2 or 3 muscle deficits (42%) compared with those without any deficits (26%) had worse 6MWD = −109 m (95% confidence interval [CI], −175 to −43), London Chest Activity of Daily Living Questionnaire = 18 (95% CI, 7-30), and St. Georgeʼs Activity Domain = 12 (95% CI, 2-21). Number of muscle deficits was associated with posttransplant hospital stay (r = 0.34, P = 0.04), but not with delisting/mortality or posttransplant 6MWD. CONCLUSIONSDeficits in quadriceps muscle strength and physical performance are common in LTx candidates and further research is needed to assess whether modifying muscle function pretransplant can lead to improved clinical outcomes.