PURPOSE The Multiple Sclerosis Quality of Life-54 (MSQOL-54) is a specific multiple sclerosis (MS) health-related quality of life inventory consisting of 52 items organized into 12 subscales plus two single items. No study was found in literature assessing its measurement invariance across language versions. We investigated whether MSQOL-54 items provide unbiased measurements of underlying constructs across Italian and English versions. METHODS Three constrained levels of measurement invariance were evaluated: configural invariance where equivalent numbers of factors/factor patterns were required; metric invariance where equivalent factor loadings were required; and scalar invariance where equivalent item intercepts between groups were required. Comparative fit index (CFI), root mean square error of approximation (RMSEA), and standardized root mean square residual (SRMR) fit indices and their changes between nested models were used to assess tenability of invariance constraints. RESULTS Overall, the dataset included 3669 MS patients: 1605 (44%) Italian, mean age 41 years, 62% women, 69% with mild level of disability; 2064 (56%) English-speaking (840 [41%] from North America, 797 [39%] from Australasia, 427 [20%] from UK and Ireland), mean age 46 years, 83% women, 54% with mild level of disability. The configural invariance model showed acceptable fit (RMSEA = 0.052, CFI = 0.904, SRMR = 0.046); imposing loadings and intercepts equality constraints produced negligible worsening of fit (ΔRMSEA < 0.001, ΔCFI = - 0.002, ΔSRMR = 0.002 for metric invariance; ΔRMSEA = 0.003, ΔCFI = - 0.013, ΔSRMR = 0.003 for scalar invariance). CONCLUSIONS These findings support measurement invariance of the MSQOL-54 across the two language versions, suggesting that the questionnaire has the same meaning and the same measurement paramaters in the Italian and English versions.

中文翻译：

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评估意大利语和英语版本中MSQOL-54的测量不变性。

目的多发性硬化症生活质量54（MSQOL-54）是一种特定的多发性硬化症（MS）健康相关的生活质量清单，包括52个项目，分为12个子量表和两个单项。在文献中未发现评估其跨语言版本的度量不变性的研究。我们调查了MSQOL-54项目是否提供了意大利语和英语版本中基础结构的无偏度量。方法评估了三个约束水平的测量不变性：配置不变性，其中需要相等数量的因子/因子模式；需要等效因子加载的度量不变性；和标量不变性，需要在组之间进行等效项截距。比较拟合指数（CFI），均方根近似误差（RMSEA），标准化的均方根残差（SRMR）拟合指数及其在嵌套模型之间的变化用于评估不变性约束的持久性。结果总体上，该数据集包括3669名MS患者：1605名（44％）意大利人，平均年龄41岁，女性62％，轻度残疾水平为69％；2064（56％）会说英语（北美的840 [41％]，澳大利亚的797 [39％]，英国和爱尔兰的427 [20％]），平均年龄46岁，女性83％，轻度54％残疾水平。构造不变模型显示出可接受的拟合度（RMSEA = 0.052，CFI = 0.904，SRMR = 0.046）；施加载荷并拦截相等约束时，拟合度的恶化可忽略不计（对于度量不变性，ΔRMSEA<0.001，ΔCFI=-0.002，ΔSRMR= 0.002;对于标量不变，ΔRMSEA= 0.003，ΔCFI=-0.013，ΔSRMR= 0.003）。