Hobart J, Lamping D, Fitzpatrick R, Riazi A, Thompson A
Neurological Outcome Measures Unit, Institute of Neurology, London, UK.
Brain. 2001 May;124(Pt 5):962-73. doi: 10.1093/brain/124.5.962.
Changes in health policy have underlined the importance of evidence-based clinical practice and rigorous evaluation of patient-based outcomes. As patient-based outcome measurement is particularly important in treatment trials of multiple sclerosis, a number of disease-specific instruments have been developed recently. One limitation of these instruments is that none was developed using the standard psychometric approach of reducing a large item pool generated from people with multiple sclerosis. Consequently, an outcome measure for clinical trials of multiple sclerosis that is disease specific and combines patient perspective with rigorous psychometric methods will complement existing instruments. The aim of this study was to develop such a measure. Standard psychometric methods were used. A pool of 129 questionnaire items was generated from interviews with 30 people with multiple sclerosis, expert opinion and literature review. The questionnaire was administered by postal survey to 1530 people selected randomly from the Multiple Sclerosis Society membership database. Redundant items and those with limited measurement properties were removed. The remaining items (n = 41) were grouped into scales using factor analysis, and then refined to form the Multiple Sclerosis Impact Scale (MSIS-29), an instrument measuring the physical (20 items) and psychological (nine items) impact of multiple sclerosis. Five psychometric properties of the MSIS-29 (data quality, scaling assumptions, acceptability, reliability and validity) were examined in a separate postal survey of 1250 Multiple Sclerosis Society members. A preliminary responsiveness study of the MSIS-29 was undertaken in 55 people admitted for rehabilitation and intravenous steroid treatment of relapses. The MSIS-29 satisfied all psychometric criteria. Data quality was excellent, missing data were low (maximum 3.9%), item test-re-test reliability was high (r = 0.65-0.90) and scale scores could be generated for >98% of respondents. Item descriptive statistics, item convergent and discriminant validity, and factor analysis indicated that it was legitimate to generate scores for MSIS-29 scales by summing items. MSIS-29 scales showed good variability, small floor and ceiling effects, high internal consistency (Cronbach's alpha <or=0.91) and high test-re-test reliability (intraclass correlation <or=0.87). Correlations with other measures and the analysis of group differences provided evidence that the MSIS-29 measures the physical and psychological impact of multiple sclerosis. Effect sizes (physical scale = 0.82, psychological scale = 0.66) demonstrated preliminary evidence of good responsiveness. These results indicate the MSIS-29 is a clinically useful and scientifically sound patient-based outcome measure of the impact of multiple sclerosis suitable for clinical trials and epidemiological studies.
卫生政策的变化凸显了循证临床实践以及对基于患者的治疗结果进行严格评估的重要性。由于基于患者的治疗结果测量在多发性硬化症治疗试验中尤为重要，最近已开发出一些针对该疾病的工具。这些工具的一个局限性在于，没有一个是采用从多发性硬化症患者中生成大量项目池的标准心理测量方法来开发的。因此，一种针对多发性硬化症临床试验的、特定于该疾病且将患者视角与严格心理测量方法相结合的治疗结果测量工具，将对现有工具起到补充作用。本研究的目的就是开发这样一种测量工具。研究采用了标准心理测量方法。通过对30名多发性硬化症患者进行访谈、征求专家意见以及文献综述，生成了包含129个问题条目的问卷库。通过邮政调查，将问卷发放给从多发性硬化症协会会员数据库中随机选取的1530人。去除冗余条目以及测量属性有限的条目。使用因子分析将剩余的条目（n = 41）分组形成量表，然后进行完善，形成了多发性硬化症影响量表（MSIS - 29），这是一种测量多发性硬化症身体（20个条目）和心理（9个条目）影响的工具。在对1250名多发性硬化症协会会员进行的另一项邮政调查中，对MSIS - 29的五个心理测量属性（数据质量、量表假设、可接受性、信度和效度）进行了检验。对55名因复发而接受康复治疗和静脉注射类固醇治疗的患者进行了MSIS - 29的初步反应性研究。MSIS - 29满足所有心理测量标准。数据质量极佳，缺失数据比例低（最高3.9%），条目重测信度高（r = 0.65 - 0.90），超过98%的受访者能够生成量表分数。条目描述性统计、条目收敛效度和区分效度以及因子分析表明，通过对条目求和来生成MSIS - 29量表分数是合理的。MSIS - 29量表显示出良好的变异性、较小的数据截断效应和天花板效应、高内部一致性（Cronbach's alpha≤0.91）以及高重测信度（组内相关系数≤0.87）。与其他测量方法的相关性以及组间差异分析提供了证据，表明MSIS - 29能够测量多发性硬化症的身体和心理影响。效应大小（身体量表 = 0.82，心理量表 = 0.66）初步证明了良好的反应性。这些结果表明，MSIS - 29是一种临床上有用且科学合理的、基于患者的多发性硬化症影响治疗结果测量工具，适用于临床试验和流行病学研究。
