BackgroundSarcopenia is a potential risk factor for adverse outcomes in haematopoietic cell transplantation (HSCT) recipients. We aimed to explore longitudinal body changes in muscle and adipose mass and their prognostic value in allogeneic HSCT‐treated severe aplastic anaemia (SAA) patients.MethodsWe retrospectively analysed consecutive SAA patients who underwent allogeneic HSCT between January 2017 and March 2022. Measurements of pectoral muscle and corresponding subcutaneous fat mass were obtained via chest computed tomography at baseline and at 1 month, 3 months, 6 months, and 12 months following HSCT. Sarcopenia was defined as pectoral muscle index (PMI) lower than the sex‐specific median at baseline. Changes in body composition over time were evaluated by generalized estimating equations. Cox regression models were used to investigate prognostic factors affecting overall survival (OS) and failure‐free survival (FFS). A nomogram was constructed from the Cox regression model for OS.ResultsWe included 298 adult SAA patients (including 129 females and 169 males) with a median age of 31 years [interquartile range (IQR), 24–39 years] at baseline. Sarcopenia was present in 148 (148/298, 50%) patients at baseline, 218 (218/285, 76%) patients post‐1 month, 209 (209/262, 80%) patients post‐3 month, 169 (169/218, 78%) patients post‐6 month, and 129 (129/181, 71%) patients post‐12 month. A significant decrease in pectoral muscle mass was observed in SAA patients from the time of transplant to 1 year after HSCT, and the greatest reduction occurred in post 1–3 months (P < 0.001). The sarcopenia group exhibited significantly lower 5‐year OS (90.6% vs. 100%, log‐rank P = 0.039) and 5‐year FFS (89.2% vs. 100%, log‐rank P = 0.021) than the nonsarcopenia group at baseline. Sarcopenia at baseline (hazard ratio, HR, 6.344; 95% confidence interval, CI: 1.570–25.538; P = 0.01; and HR, 3.275; 95% CI: 1.159–9.252; P = 0.025, respectively) and the delta value of the PMI at 6 months post‐transplantation (ΔPMI6) (HR, 0.531; 95% CI: 0.374–0.756; P < 0.001; and HR, 0.666; 95% CI: 0.505–0.879; P = 0.004, respectively) were demonstrated to be independent prognostic factors for OS and FFS in SAA patients undergoing HSCT, and were used to construct the nomogram. The C‐index of the nomogram was 0.75, and the calibration plot showed good agreement between the predictions made by the nomogram and actual observations.ConclusionsSarcopenia persists in SAA patients from the time of transplant to the 1‐year follow‐up after HSCT. Both sarcopenia at baseline and at 6 months following HSCT are associated with poor clinical outcomes, especially in patients with persistent muscle mass loss up to 6 months after transplantation.

中文翻译：

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异基因造血细胞移植后严重再生障碍性贫血幸存者肌肉减少症的演变和影响

背景肌肉减少症是造血细胞移植（HSCT）受者不良结果的潜在危险因素。我们的目的是探讨同种异体 HSCT 治疗的严重再生障碍性贫血 (SAA) 患者肌肉和脂肪量的纵向身体变化及其预后价值。方法我们回顾性分析了 2017 年 1 月至 2022 年 3 月期间接受同种异体 HSCT 的连续 SAA 患者。通过胸部计算机断层扫描在基线以及 HSCT 后 1 个月、3 个月、6 个月和 12 个月时获得相应的皮下脂肪量。肌肉减少症被定义为基线时胸肌指数（PMI）低于性别特异性中位数。通过广义估计方程评估身体成分随时间的变化。 Cox回归模型用于研究影响总生存期（OS）和无失败生存期（FFS）的预后因素。根据 OS 的 Cox 回归模型构建列线图。结果我们纳入了 298 名成年 SAA 患者（包括 129 名女性和 169 名男性），基线时中位年龄为 31 岁[四分位距 (IQR)，24-39 岁]。基线时有 148 名患者 (148/298, 50%) 存在肌少症，1 个月后有 218 名患者 (218/285, 76%) 存在肌少症，3 个月后有 209 名患者 (209/262, 80%) 存在肌少症，3 个月后有 169 名患者 (169 /218, 78%) 名患者在 6 个月后，129 (129/181, 71%) 名患者在 12 个月后。从移植时到 HSCT 后 1 年，SAA 患者的胸肌质量显着下降，最大下降发生在移植后 1-3 个月（磷< 0.001）。肌肉减少症组表现出显着较低的 5 年 OS（90.6% vs. 100%，对数秩磷= 0.039）和 5 年 FFS（89.2% 与 100%，对数秩磷= 0.021）比基线时非肌肉减少症组。基线时肌肉减少症（风险比，HR，6.344；95% 置信区间，CI：1.570–25.538；磷= 0.01;人力资源，3.275； 95% CI：1.159–9.252；磷分别 = 0.025）和移植后 6 个月时 PMI 的增量值 (ΔPMI6)（HR，0.531；95% CI：0.374-0.756；磷< 0.001；心率，0.666； 95% CI：0.505–0.879；磷= 0.004，分别）被证明是接受 HSCT 的 SAA 患者 OS 和 FFS 的独立预后因素，并用于构建列线图。列线图的 C 指数为 0.75，校准图显示列线图的预测与实际观察结果之间具有良好的一致性。结论 SAA 患者从移植时到 HSCT 后 1 年随访期间持续存在肌少症。基线时和 HSCT 后 6 个月时的肌肉减少症均与不良临床结果相关，特别是对于移植后长达 6 个月持续肌肉质量损失的患者。