Laboratory of Research in Respiratory Physiotherapy (LFIP), Department of Physiotherapy, State University of Londrina (UEL), Londrina, Brazil.
Eur J Clin Nutr. 2017 Nov;71(11):1285-1290. doi: 10.1038/ejcn.2017.105. Epub 2017 Jul 19.
BACKGROUND/OBJECTIVES: None of the cutoff points for fat-free mass index (FFMI) were tested for the Brazilian population, and it is unknown whether the available ones are able to discriminate extrapulmonary disease manifestations. This cross-sectional study aims to develop and validate a cutoff point for FFM depletion based on Brazilian patients with chronic obstructive pulmonary disease (COPD) and to verify its association and of previously published cutoffs with extrapulmonary manifestations.
SUBJECTS/METHODS: A new cutoff point was obtained from the best FFMI value for discrimination of preserved exercise capacity in a sample of patients (n=57). The discriminative capacity was assessed in another sample (n=96). The new cutoff point and other previously published ones were tested to discriminate low exercise capacity, physical inactivity, sedentary lifestyle and low quality of life. A receiver operation characteristics curve with area under the curve (AUC) value was plotted and each cutoff points' discriminative capacity was calculated. Cox regression and Kaplan-Meier method assessed the association between the cutoff points and mortality.
The new cutoff points for FFMI were 14.65 kg/m for women (AUC=0.744; sensitivity (Se)=0.88; specificity (Sp)=0.60) and 20.35 kg/m for men (AUC=0.565; Se=0.36; Sp=0.81). The new cutoffs were the best to discriminate poor exercise capacity assessed by walked distance in % predicted and quality of life. Only the new cutoff point was associated with mortality (HR=2.123; 95% CI: 1.03-4.33, P=0.039, log rank P=0.035).
Only the new cutoff point was associated with all-cause mortality, and it had the highest discriminating capacity for exercise capacity and quality of life in Brazilian patients with COPD.
背景/目的：目前还没有针对巴西人群的无脂肪质量指数（FFMI）截断值，也不知道现有的截断值是否能够区分肺外疾病表现。本横断面研究旨在为巴西慢性阻塞性肺疾病（COPD）患者制定和验证基于 FFMI 的肌肉减少症截断值，并验证其与以前发表的截断值与肺外表现的相关性。
受试者/方法：从一组患者（n=57）中获得了最佳 FFMI 值以区分保留运动能力的新截断值。在另一组样本（n=96）中评估了区分能力。测试了新的截断值和其他以前发表的截断值，以区分低运动能力、身体活动不足、久坐的生活方式和低生活质量。绘制了接受者操作特征曲线，计算了曲线下面积（AUC）值，并计算了每个截断值的区分能力。Cox 回归和 Kaplan-Meier 方法评估了截断值与死亡率之间的关系。
女性 FFMI 的新截断值为 14.65kg/m（AUC=0.744；灵敏度（Se）=0.88；特异性（Sp）=0.60），男性为 20.35kg/m（AUC=0.565；Se=0.36；Sp=0.81）。新的截断值是区分通过预测步行距离和生活质量评估的运动能力差的最佳指标。只有新的截断值与死亡率相关（HR=2.123；95%CI：1.03-4.33，P=0.039，对数秩检验 P=0.035）。
只有新的截断值与全因死亡率相关，并且它对巴西 COPD 患者的运动能力和生活质量具有最高的区分能力。
