St. Mark's Hospital, Harrow, United Kingdom; Department of Surgery and Cancer, Imperial College, London, United Kingdom.
St. Mark's Hospital, Harrow, United Kingdom.
Clin Nutr. 2020 Mar;39(3):829-836. doi: 10.1016/j.clnu.2019.03.015. Epub 2019 Mar 19.
BACKGROUND & AIMS: Sarcopenia occurs in patients with intestinal failure (IF) and has been associated with poorer survival in several chronic diseases. CT can measure sarcopenia through a L3 skeletal muscle index (LSMI). We aim to describe the prevalence of sarcopenia in a section of our IF population using LSMI, & evaluate the effect of home parenteral support (PS) on LSMI & survival. Additionally, we aim to assess any association between LSMI, BMI & other anthropometric measurements.
IF patients on PS treated at St Mark's Hospital between 1/1/2006-1/10/2016 were identified from a prospectively maintained database. Patients were included if they were on PS & had 2 CTs: the first ≤30 days before start of HPN (pre-PS); the second ≥100 days from PS start (post-PS). Patient records were reviewed to obtain clinical & demographic information & date of death. Anthropometric measurements & BMI contemporaneous to CT scans were recorded.
64 patients met inclusion criteria (M:F 1:1). 83% of our cohort had LSMI below previously published thresholds for sarcopenia. Mean (SD) pre-PS LSMI was 36.5 (6.8)cm/m. Mean BMI pre-PS was 22.1 (4.8) kg/m. Both BMI (22.1 kg/m to 23.5 kg/m) p < 0.001) & LSMI (36.5 cm/m to 38.4 cm/m) (p = 0.003) increased post-PS. A positive correlation was seen between BMI & LSMI pre (r = 0.47 p < 0.001) & post-PS (r = 0.37 p = 0.003). No correlation was seen between LSMI & anthropometric measurements pre-PS (p = 0.78) or post-PS (p = 0.96). 11 (17%) patients died during the study period; a low LSMI pre-PS was not a risk factor for mortality (HR 0.97 p = 0.55).
This study is the first to look at sarcopenia & survival using CT defined LSMI (CT-LSMI) in the IF population. 83% of our cohort had a pre-PS LSMI below previously published thresholds, yet we found no relationship between lower baseline LSMI & survival. This may reflect the heterogeneity of the prognoses of the IF population, or that parenteral nutrition itself affects survival. Our study showed that LSMI & BMI improved following PS but demonstrated that other anthropometric measurements had poor correlation with LSMI & showed no significant improvement overall after PS, confirming the known problems of inter-operator & patient variability of these measurements. Whilst we found significant correlation between LSMI & BMI, BMI significantly underestimated the presence & degree of sarcopenia. LSMI has the potential to provide an objective & reproducible measure of sarcopenia in IF. Future larger studies should be performed to evaluate associations with patient outcomes & utility in clinical decision making.
肌肉减少症发生于肠衰竭（IF）患者中，并且与多种慢性疾病的生存预后较差相关。CT 可通过 L3 骨骼肌指数（LSMI）来测量肌肉减少症。我们旨在通过 LSMI 描述我们 IF 人群中的肌肉减少症患病率，并评估家庭肠外支持（PS）对 LSMI 和生存的影响。此外，我们旨在评估 LSMI、BMI 和其他人体测量学指标之间的任何关联。
从 2006 年 1 月 1 日至 2016 年 1 月 10 日期间，从 St Mark's 医院前瞻性维护的数据库中确定接受 PS 治疗的 IF 患者。如果患者接受 PS 治疗且有 2 次 CT 扫描：第一次在开始 HPN 前≤30 天（PS 前）；第二次在开始 PS 后≥100 天（PS 后）。回顾患者记录以获取临床和人口统计学信息以及死亡日期。记录 CT 扫描时的人体测量学指标和 BMI。
符合纳入标准的 64 名患者（1:1 的男女比例）。我们队列中的 83%患者的 PS 前 LSMI 低于先前发表的肌肉减少症阈值。PS 前的平均（SD）LSMI 为 36.5（6.8）cm/m。PS 前的平均 BMI 为 22.1（4.8）kg/m。BMI（22.1 kg/m 至 23.5 kg/m，p < 0.001）和 LSMI（36.5 cm/m 至 38.4 cm/m，p = 0.003）均在 PS 后增加。PS 前后 BMI 和 LSMI 之间存在正相关（r = 0.47，p < 0.001）。PS 前后 LSMI 与人体测量学指标之间均无相关性（p = 0.78 或 p = 0.96）。研究期间 11（17%）名患者死亡；PS 前低 LSMI 不是死亡的危险因素（HR 0.97，p = 0.55）。
本研究首次使用 CT 定义的 LSMI（CT-LSMI）观察 IF 人群中的肌肉减少症和生存情况。我们队列的 83%患者的 PS 前 LSMI 低于先前发表的阈值，但我们未发现较低的基线 LSMI 与生存之间存在关联。这可能反映了 IF 人群预后的异质性，或者肠外营养本身会影响生存。我们的研究表明，PS 后 LSMI 和 BMI 有所改善，但表明其他人体测量学指标与 LSMI 的相关性较差，总体上 PS 后无明显改善，证实了这些测量方法的操作者间和患者间变异性的已知问题。虽然我们发现 LSMI 和 BMI 之间存在显著相关性，但 BMI 显著低估了肌肉减少症的存在和严重程度。LSMI 有可能提供 IF 中肌肉减少症的客观、可重复的测量方法。未来应进行更大规模的研究，以评估其与患者结局和临床决策中的应用的关联。
