Johansson Sverker, Kottorp Anders, Lee Kathryn A, Gay Caryl L, Lerdal Anners
Department of Neurobiology, Care sciences and Society, Karolinska Institutet, Stockholm, Sweden.
Health Qual Life Outcomes. 2014 Feb 22;12:24. doi: 10.1186/1477-7525-12-24.
Fatigue is a disabling symptom associated with reduced quality of life in various populations living with chronic illnesses. The transfer of knowledge about fatigue from one group to another is crucial in both research and healthcare. Outcomes should be validly and reliably comparable between groups and should not be unduly influenced by diagnostic variations. The present study evaluates whether the Fatigue Severity Scale 7-item version (FSS-7) demonstrates similar item hierarchy across people with multiple sclerosis, stroke or HIV/AIDS to ensure valid comparisons between groups, and provide further evidence of internal scale validity.
A secondary comparative analysis was performed using data from three different studies of three different chronic illnesses: multiple sclerosis, stroke and HIV/AIDS. Each of these studies had previously concluded that the FSS-7 has better psychometric properties than the original FSS for measuring fatigue interference. Data from 224 people with multiple sclerosis, 104 people with stroke and 316 people with HIV/AIDS were examined. Item response theory and a Rasch model were chosen to analyze the similarity of the FSS-7 item hierarchy across the three diagnostic groups
Cross-sample differences were found for items #3, #5, #6 and #9 for two of the three samples, which raise questions about item validity across groups. However, disease-specific and disease-generic Rasch measures were similar across samples, indicating that individual fatigue interference measures in these three chronic illnesses might still be reliably comparable using the FSS-7.
Some items performed differently between the three samples but did not bias person measures, thereby indicating that fatigue interference in these illnesses might still be reliably compared using FSS-7 scores. However, caution is warranted when comparing fatigue raw sum scores directly across diagnostic groups using the FSS-7. Further studies of the scale are needed in other types of chronic illnesses.
疲劳是一种致残症状，与各种慢性病患者的生活质量下降相关。在研究和医疗保健中，将有关疲劳的知识从一个群体传递到另一个群体至关重要。各群体之间的结果应具有有效且可靠的可比性，并且不应受到诊断差异的过度影响。本研究评估疲劳严重程度量表7项版本（FSS-7）在多发性硬化症、中风或艾滋病毒/艾滋病患者中是否表现出相似的项目层次结构，以确保各群体之间的有效比较，并提供量表内部效度的进一步证据。
使用来自三项不同慢性病（多发性硬化症、中风和艾滋病毒/艾滋病）的三项不同研究的数据进行二次比较分析。这些研究先前均得出结论，FSS-7在测量疲劳干扰方面比原始FSS具有更好的心理测量特性。对224名多发性硬化症患者、104名中风患者和316名艾滋病毒/艾滋病患者的数据进行了检查。选择项目反应理论和Rasch模型来分析FSS-7项目层次结构在三个诊断组中的相似性。
在三个样本中的两个样本中，发现第3、5、6和9项存在跨样本差异，这对各群体间项目的效度提出了疑问。然而，疾病特异性和疾病通用的Rasch测量在各样本间相似，表明使用FSS-7对这三种慢性病中的个体疲劳干扰测量仍可能具有可靠的可比性。
三个样本之间某些项目的表现有所不同，但并未影响个体测量结果，因此表明使用FSS-7分数仍可可靠地比较这些疾病中的疲劳干扰情况。然而，在使用FSS-7直接比较不同诊断组的疲劳原始总分时需要谨慎。还需要在其他类型的慢性病中对该量表进行进一步研究。
