Abstract：
OBJECTIVE: There is an emerging and urgent need to identify biomarkers of sarcopenia. A novel sarcopenia index (SI), based on serum creatinine and cystatin C, has emerged as a potential biomarker for use. The SI can predict clinical outcomes and discriminate between the presence of sarcopenia in a range of chronic and acute conditions. However, the SI has not yet been tested in a large real-world general population dataset. This study aimed to investigate the accuracy of the SI in the identification of sarcopenia in a large prospective general population cohort.
METHODS: Data were taken from UK Biobank, a large prospective epidemiological study in the United Kingdom (UK). Serum creatinine and cystatin C values were used to calculate the SI [creatinine (mg/dl)/cystatin C (mg/dl) × 100]. Probable sarcopenia was defined by maximum handgrip strength (HGS). Muscle mass was assessed using bioelectrical impedance analysis. Low muscle mass was defined as an appendicular lean mass (ALM) index below prespecified thresholds. Confirmed sarcopenia was defined as both low HGS and low muscle mass. Pearson correlation coefficients and logistic regression were used to explore the association between various sarcopenia traits (probable sarcopenia, low ALM index, and confirmed sarcopenia) and the SI. The diagnostic value of the SI was investigated using the area under the receiver operating characteristic curve (area under the curve, AUC).
RESULTS: 458,702 participants were included in the analysis (46.4% males, mean age, males: 68.7 (±8.2) years; females: 68.2 (±8.0) years)). Probable sarcopenia was observed in 4.5% of males and 6.1% of females; low ALM index in 2.8% of males and 0.7% of females; confirmed sarcopenia in 0.3% of males and 0.1% of females. SI was significantly lower in individuals with confirmed sarcopenia (males: 86.3 ± 16.6 vs. 99.5 ± 15.3, p < .01; females: 73.6 ± 13.7 vs. 84.6 ± 14.0, p < .01). For every 1-unit increase in the SI, the odds of confirmed sarcopenia were reduced by 5% in males (odds ratio (OR): 0.95, p < 0.001) and 7% in females (OR: 0.923, p < 0.001). The AUC showed acceptable discriminative ability of confirmed sarcopenia (males: AUC = 0.731; females: AUC = 0.711).
CONCLUSIONS: Using a large real-world dataset of almost half a million people, our study indicated the SI has acceptable diagnostic accuracy when identifying those with sarcopenia and may be a useful biomarker to aid the stratification of those at risk and in need of intervention.
METHODS: Data were taken from UK Biobank, a large prospective epidemiological study in the United Kingdom (UK). Serum creatinine and cystatin C values were used to calculate the SI [creatinine (mg/dl)/cystatin C (mg/dl) × 100]. Probable sarcopenia was defined by maximum handgrip strength (HGS). Muscle mass was assessed using bioelectrical impedance analysis. Low muscle mass was defined as an appendicular lean mass (ALM) index below prespecified thresholds. Confirmed sarcopenia was defined as both low HGS and low muscle mass. Pearson correlation coefficients and logistic regression were used to explore the association between various sarcopenia traits (probable sarcopenia, low ALM index, and confirmed sarcopenia) and the SI. The diagnostic value of the SI was investigated using the area under the receiver operating characteristic curve (area under the curve, AUC).
RESULTS: 458,702 participants were included in the analysis (46.4% males, mean age, males: 68.7 (±8.2) years; females: 68.2 (±8.0) years)). Probable sarcopenia was observed in 4.5% of males and 6.1% of females; low ALM index in 2.8% of males and 0.7% of females; confirmed sarcopenia in 0.3% of males and 0.1% of females. SI was significantly lower in individuals with confirmed sarcopenia (males: 86.3 ± 16.6 vs. 99.5 ± 15.3, p < .01; females: 73.6 ± 13.7 vs. 84.6 ± 14.0, p < .01). For every 1-unit increase in the SI, the odds of confirmed sarcopenia were reduced by 5% in males (odds ratio (OR): 0.95, p < 0.001) and 7% in females (OR: 0.923, p < 0.001). The AUC showed acceptable discriminative ability of confirmed sarcopenia (males: AUC = 0.731; females: AUC = 0.711).
CONCLUSIONS: Using a large real-world dataset of almost half a million people, our study indicated the SI has acceptable diagnostic accuracy when identifying those with sarcopenia and may be a useful biomarker to aid the stratification of those at risk and in need of intervention.
摘要：
目的：目前正在出现并迫切需要鉴定肌肉减少症的生物标志物。一种新的肌肉减少症指数(SI)基于血清肌酐和胱抑素C，已经成为一种潜在的生物标志物。SI可以预测临床结果并在一系列慢性和急性病症中区分少肌症的存在。然而,SI尚未在大型真实世界的一般人群数据集中进行测试。这项研究旨在调查SI在大型前瞻性普通人群队列中识别肌肉减少症的准确性。
方法：数据来自英国生物银行，英国的一项大型前瞻性流行病学研究。使用血清肌酐和胱抑素C值计算SI[肌酐（mg/dl）/胱抑素C（mg/dl）×100]。可能的肌肉减少症由最大握力（HGS）定义。使用生物电阻抗分析评估肌肉质量。低肌肉质量定义为阑尾瘦质量（ALM）指数低于预定阈值。确认的肌肉减少症被定义为低HGS和低肌肉质量。使用Pearson相关系数和logistic回归来探索各种少肌症性状之间的关联（可能的少肌症，ALM指数低，并确认肌少症）和SI。SI的诊断值是使用接收器工作特性曲线下的面积（曲线下的面积，AUC)。
结果：458,702名参与者被纳入分析（男性占46.4％，平均年龄,男性：68.7（±8.2）岁；女性：68.2（±8.0）岁）。在4.5％的男性和6.1％的女性中观察到可能的肌肉减少症；2.8％的男性和0.7％的女性的ALM指数较低；在0.3％的男性和0.1％的女性中确认了肌肉减少症。确诊肌少症患者的SI显着降低（男性：86.3±16.6vs.99.5±15.3，p<.01；女性：73.6±13.7vs.84.6±14.0，p<0.01）。SI每增加1个单位，男性患者发生肌少症的几率降低5%(比值比(OR):0.95,p<0.001),女性患者则降低7%(OR:0.923,p<0.001).AUC显示可接受的经证实的肌少症的辨别能力(男性:AUC=0.731;女性:AUC=0.711)。
结论：使用近50万人的大型现实世界数据集，我们的研究表明,SI在识别少肌症患者时具有可接受的诊断准确性,并且可能是一种有用的生物标志物,有助于对有危险和需要干预的患者进行分层.
方法：数据来自英国生物银行，英国的一项大型前瞻性流行病学研究。使用血清肌酐和胱抑素C值计算SI[肌酐（mg/dl）/胱抑素C（mg/dl）×100]。可能的肌肉减少症由最大握力（HGS）定义。使用生物电阻抗分析评估肌肉质量。低肌肉质量定义为阑尾瘦质量（ALM）指数低于预定阈值。确认的肌肉减少症被定义为低HGS和低肌肉质量。使用Pearson相关系数和logistic回归来探索各种少肌症性状之间的关联（可能的少肌症，ALM指数低，并确认肌少症）和SI。SI的诊断值是使用接收器工作特性曲线下的面积（曲线下的面积，AUC)。
结果：458,702名参与者被纳入分析（男性占46.4％，平均年龄,男性：68.7（±8.2）岁；女性：68.2（±8.0）岁）。在4.5％的男性和6.1％的女性中观察到可能的肌肉减少症；2.8％的男性和0.7％的女性的ALM指数较低；在0.3％的男性和0.1％的女性中确认了肌肉减少症。确诊肌少症患者的SI显着降低（男性：86.3±16.6vs.99.5±15.3，p<.01；女性：73.6±13.7vs.84.6±14.0，p<0.01）。SI每增加1个单位，男性患者发生肌少症的几率降低5%(比值比(OR):0.95,p<0.001),女性患者则降低7%(OR:0.923,p<0.001).AUC显示可接受的经证实的肌少症的辨别能力(男性:AUC=0.731;女性:AUC=0.711)。
结论：使用近50万人的大型现实世界数据集，我们的研究表明,SI在识别少肌症患者时具有可接受的诊断准确性,并且可能是一种有用的生物标志物,有助于对有危险和需要干预的患者进行分层.
