McClean Andrew, Morgan Matthew D, Basu Neil, Bosch Jos A, Nightingale Peter, Jones David, Harper Lorraine
Centre for Translational Inflammation Research, University of Birmingham, Birmingham, UK.
School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK.
Arthritis Care Res (Hoboken). 2016 Sep;68(9):1332-9. doi: 10.1002/acr.22827. Epub 2016 Jul 27.
This study investigated differences in cardiorespiratory fitness, muscular function, perceived exertion, and anxiety/depression between patients and healthy controls (HCs) and assessed which of these variables may account for the fatigue experienced by patients.
Fatigue was measured in 48 antineutrophil cytoplasmic antibody-associated vasculitis patients and 41 healthy controls using the Multidimensional Fatigue Inventory (MFI-20), focusing on the physical component. Quality of life, anxiety/depression, and sleep quality were assessed by validated questionnaires. Muscle mass was measured by dual-energy x-ray absorptiometry scan, strength as the maximal voluntary contraction (MVC) force, and endurance as sustained isometric contraction at 50% MVC of the quadriceps. Voluntary activation was assessed by superimposed electrical stimulation. Cardiorespiratory fitness ( ˙Vo2 max and oxygen pulse [O2 pulse]) and perceived exertion (Borg scale) were measured during progressive submaximal exercise.
Patients reported elevated physical fatigue scores compared to HCs (patients MFI-20 physical 13 [interquartile range (IQR) 8-16], HCs MFI-20 physical 5.5 [IQR 4-8]; P < 0.001). Muscle mass was the same in both groups, but MVC and time to failure in the endurance test were lower due to reduced voluntary activation in patients. Estimated ˙Vo2 max and O2 pulse were the same in both groups. For the same relative workload, patients reported higher ratings of perceived exertion, which correlated with reports of MFI-20 physical fatigue (R(2) = 0.2). Depression (R(2) = 0.6), anxiety (R(2) = 0.3), and sleep disturbance (R(2) = 0.3) were all correlated with MFI-20 physical fatigue.
These observations suggest that fatigue in patients is of a central rather than peripheral origin, supported by associations of fatigue with heightened perception of exertion, depression, anxiety, and sleep disturbance but normal muscle and cardiorespiratory function.
本研究调查了患者与健康对照者（HCs）在心肺适能、肌肉功能、主观用力感觉以及焦虑/抑郁方面的差异，并评估了这些变量中哪些可能是导致患者疲劳的原因。
使用多维疲劳量表（MFI - 20）对48例抗中性粒细胞胞浆抗体相关性血管炎患者和41例健康对照者进行疲劳测量，重点关注身体维度。通过经过验证的问卷评估生活质量、焦虑/抑郁和睡眠质量。通过双能X线吸收法扫描测量肌肉量，以最大自主收缩（MVC）力作为力量指标，以股四头肌在50%MVC时的持续等长收缩作为耐力指标。通过叠加电刺激评估自主激活情况。在进行递增亚极量运动期间测量心肺适能（最大摄氧量[˙Vo2 max]和氧脉搏[O2脉搏]）和主观用力感觉（Borg量表）。
与HCs相比，患者报告的身体疲劳得分更高（患者MFI - 20身体维度得分13[四分位数间距（IQR）8 - 16]，HCs MFI - 20身体维度得分5.5[IQR 4 - 8]；P < 0.001）。两组的肌肉量相同，但由于患者的自主激活降低，MVC和耐力测试中的疲劳时间较低。两组的估计˙Vo2 max和O2脉搏相同。对于相同的相对工作量，患者报告的主观用力感觉评分更高，这与MFI - 20身体疲劳报告相关（R(2) = 0.2）。抑郁（R(2) = 0.6）、焦虑（R(2) = 0.3）和睡眠障碍（R(2) = 0.3）均与MFI - 20身体疲劳相关。
这些观察结果表明，患者的疲劳源于中枢而非外周，疲劳与用力感觉增强、抑郁、焦虑和睡眠障碍相关，但肌肉和心肺功能正常，这支持了上述观点。
