A comparison of health-related factors between patients diagnosed with ME/CFS and patients with a related symptom picture but no ME/CFS diagnosis: a cross-sectional exploratory study

Background: In chronic fatigue syndrome/myalgic encephalomyelitis (ME/CFS), the capacity for activity and participation is strongly limited. The disease definition is very broad, and considering the lack of evidence for best treatment, it is important to understand what is ME/CFS-specific in the biopsychosocial perspective in comparison with similar syndromes. The objective was to study the difference between those diagnosed with ME/CFS and those with similar symptoms but no ME/CFS diagnosis for self-perceived level of physical activity, work ability, anxiety/depression, and health-related quality of life. Methods: This was a clinical cross-sectional study with data collected from mailed questionnaires. The following variables were compared between patients diagnosed with ME/CFS (n = 205) and those with similar symptoms but no diagnosis (n = 57); level of physical activity, Work ability index (WAI), Hospital anxiety and depression scale (HAD-A/HAD-D), and RAND-36 Physical functioning, Role limitations due to physical health problems, Role limitations due to personal or emotional problems, Social functioning, Energy/fatigue, Bodily pain, Emotional well-being, and General health perceptions. The Chi-squared test (nominal data), the Mann-Whitney U test, the Student's t test and regression analysis were used to analyze the data. Results: The group diagnosed with ME/CFS had a more impaired physical and mental exertion ability as compared to the group that had similar symptoms but was not diagnosed with ME/CFS, shown by a RAND-36 lower index of physical role functioning, social functioning, energy, worse pain and poorer overall health (p <= 0.05). In contrast, no significant group differences emerged for weekly level of physical activity, work ability, anxiety/depression, and RAND-36 Emotional role limitation and well-being. Conclusion: Our results indicate that those with a diagnosis of ME/CFS are characterized by an impaired ability for physical or mental exertion, worse pain, and poorer overall health as compared to individuals with similar symptoms but for whom ME/CFS-diagnosis was not established. The results may be cautiously interpreted as support when focusing on patients' self-care in terms of management of energy levels. The results must however be verified in future studies.