Assessment of severity scales and their use in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis

Abstract

Objectives: Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) is a physical and cognitive disabling illness, characterised predominantly by severe fatigue and a range of physiological symptoms. Variation in CFS/ME symptom severity is recognised although few studies examine CFS/ME patients who are severely ill or different severity subgroups. Discrepancies in symptom severity between patients may highlight the importance of assessing and distinguishing severe CFS/ME patients based on their symptoms, both physically and mentally. This study aimed to assess severity scales in CFS/ME by determining common differences in severity scales between patients who were moderately and severely affected. Methods: A number of severity scales have been assessed in relation to their efficiency in measuring symptom severity in CFS/ME. Severity scales, such as the Karnofsky Performance Scale (KPS) and Fatigue Severity Scale (FSS) were used to classify CFS/ME patients as either moderate or severely affected. The results of the severity scales were assessed to determine if significant differences are shown between severity groups. These differences can be effective and important in determining severity subgroups in research. Results: The analysis of severity scales demonstrated subgroup distinction between moderate and severe CFS/ME patients was successfully classified in this study, using a number of severity scales. Conclusion: The heterogeneous nature of the illness suggests that severity subgroups may be related to inconsistencies in research. It is necessary that severity scales are used to assess CFS/ME in both clinical and research settings to identify severity subgroups. A consistent and distinguishable criteria is necessary to characterise CFS/ME severity subgroups and improve the accuracy of diagnosis and research.