Sethna Christine B, Salerno Ann E, McBride Michael G, Shults Justine, Paridon Stephen M, Sharma Neha, Meyers Kevin E C, Leonard Mary B
Department of Pediatrics, Division of Nephrology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Transplantation. 2009 Aug 15;88(3):395-401. doi: 10.1097/TP.0b013e3181aed7d1.
The impact of body size, fat-free mass (FFM), and fat mass (FM) on cardiorespiratory fitness in pediatric renal transplant recipients (TX) has not been established. Study objectives were to assess maximal oxygen consumption (VO2max) in TX and controls, adjusted for body composition, and to identify risk factors for reduced fitness in TX.
Cycle ergometry and dual-energy X-ray absorptiometry were obtained in 50 TX and 70 controls, ages 8 to 21 years. Control recruitment was targeted to include obese subjects with body mass index Z-scores comparable with TX. Allometric regression models were used.
TX had significantly lower height Z-scores (P<0.001) and comparable body mass index Z-scores. VO2max per body weight (mL/kg/min) and per FFM (mL/kgFFM/min) did not differ between groups. However, VO2max was 13% lower (95% CI 18, 8; P<0.001) in TX, compared with controls, adjusted for FM, FFM, sex, and race. Greater FFM, lower FM, non-black race, and male sex were independently associated with greater VO2max. Within TX, hemoglobin levels were positively associated with VO2max (P=0.04) and sirolimus use was associated with lower VO2max (P<0.01).
TX had significant VO2max deficits that were not captured by conventional measures (mL/kg/min). Greater FM was an independent risk factor for low VO2max. Lower fitness in TX may be related to sirolimus effects on skeletal muscle.
身体大小、去脂体重（FFM）和脂肪量（FM）对小儿肾移植受者（TX）心肺适能的影响尚未明确。研究目的是评估经身体成分校正后的TX和对照组的最大摄氧量（VO2max），并确定TX中体能下降的危险因素。
对50名年龄在8至21岁的TX患者和70名对照组进行了蹬车测力和双能X线吸收法检测。对照组的招募目标包括体重指数Z评分与TX相当的肥胖受试者。使用了异速生长回归模型。
TX患者的身高Z评分显著更低（P<0.001），而体重指数Z评分相当。两组之间每体重（mL/kg/min）和每FFM（mL/kgFFM/min）的VO2max没有差异。然而，经FM、FFM、性别和种族校正后，TX患者的VO2max比对照组低13%（95%CI 18, 8；P<0.001）。更大的FFM、更低的FM、非黑人种族和男性性别与更高的VO2max独立相关。在TX患者中，血红蛋白水平与VO2max呈正相关（P=0.04），而使用西罗莫司与更低的VO2max相关（P<0.01）。
TX患者存在显著的VO2max缺陷，这是传统测量方法（mL/kg/min）无法捕捉到的。更高的FM是VO2max低的独立危险因素。TX患者体能较低可能与西罗莫司对骨骼肌的影响有关。
