World Health Organization Collaborating Center for Public Health Aspects of Musculoskeletal Health and Ageing, Department of Public Health, Epidemiology and Health Economics, University of Liège, Liège, Belgium.
Faculty of Medicine, Vilnius University, Vilnius, Lithuania.
PLoS One. 2019 Apr 29;14(4):e0216065. doi: 10.1371/journal.pone.0216065. eCollection 2019.
The Sarcopenia Quality of Life (SarQoL) questionnaire, a sarcopenia-specific patient-reported outcome measure, evaluates quality of life with 55 items. It produces 7 domain scores and 1 overall quality of life score, all between 0 and 100 points. This study aims to contribute to the interpretation of the SarQoL scores by calculating the standard error of measurement (SEM) and smallest detectable change (SDC) in a sample of subjects from 9 studies.
Subjects from 9 studies (conducted in Belgium, Brazil, Czech Republic, England, Greece, Lithuania, Poland and Spain) were included. The SEM, a measure of the error in the scores that is not due to true changes, was calculated by dividing the standard deviation of the difference between test and retest scores (SDdiff) by √2. The SDC, defined as change beyond measurement error, was calculated by multiplying SDdiff by 1.96. Bland-Altman plots were assessed for the presence of systematic errors.
A total of 278 sarcopenic subjects, aged 77.67 ± 7.64 years and 61.5% women, were included. The SEM for the overall SarQoL score ranged from 0.18 to 4.20 points for the individual studies, and was 2.65 points when all subjects were analyzed together. The SDC for the overall score ranged from 0.49 to 11.65 points for the individual studies, and was 7.35 points for all subjects. The Bland-Altman plots revealed no systematic errors in the questionnaire.
This study shows that, for individual subjects, a change in overall quality of life of at least 7.35 points (on a scale from 0 to 100) would have to be observed to confirm that a true change, beyond measurement error, has occurred. It also demonstrated that the SarQoL questionnaire is a precise instrument, with the observed scores within less than 3 points of the theoretical "true score".
肌少症生活质量（SarQoL）问卷是一种肌少症特异性患者报告结局测量工具，用 55 个条目评估生活质量。它产生 7 个领域评分和 1 个总体生活质量评分，均在 0 到 100 分之间。本研究旨在通过计算 9 项研究中受试者样本的测量误差（SEM）和最小可检测变化（SDC），为 SarQoL 评分的解释做出贡献。
纳入来自 9 项研究的受试者（在比利时、巴西、捷克共和国、英国、希腊、立陶宛、波兰和西班牙进行）。SEM 是指分数中的误差，不是由于真实变化引起的，通过将测试和重测分数之间的差异标准差（SDdiff）除以 √2 来计算。SDC 定义为超出测量误差的变化，通过将 SDdiff 乘以 1.96 来计算。评估 Bland-Altman 图是否存在系统误差。
共纳入 278 名肌少症受试者，年龄 77.67 ± 7.64 岁，61.5%为女性。个体研究中，整体 SarQoL 评分的 SEM 范围为 0.18 至 4.20 分，所有受试者分析时为 2.65 分。个体研究中，整体评分的 SDC 范围为 0.49 至 11.65 分，所有受试者为 7.35 分。Bland-Altman 图显示问卷中没有系统误差。
本研究表明，对于个体受试者，总体生活质量至少要发生 7.35 分（0 至 100 分）的变化，才能确认发生了真实变化，而不仅仅是测量误差。它还表明，SarQoL 问卷是一种精确的工具，观察到的分数与理论“真实分数”相差不到 3 个点。
