Phenotypes of Chronic Fatigue Syndrome in Children and Young People

OBJECTIVE: To investigate the heterogeneity of chronic fatigue syndrome (CFS/ME) in children and young people. SETTING: Regional specialist CFS/ME service. Patients: Children and young people aged <19 years old. METHODS: Exploratory factor analysis was performed on symptoms present at assessment in 333 children and young people with CFS/ME. Linear and logistic regression analysis of data from self completed assessment forms was used to explore the associations between the retained factors and sex, age, length of illness, depression, anxiety and markers of severity (fatigue, physical function, pain and school attendance). RESULTS: Three phenotypes were identified using factor analysis: Musculoskeletal (Factor 1) had loadings on muscle and joint pain and hypersensitivity to touch, and was associated with worse fatigue (regression coefficient 0.47, 95% CI 0.25, 0.68, p