Differences between Portuguese and Brazilian Patients with Fibromyalgia Syndrome: Exploring the Associations across Age, Time of Diagnosis, and Fatigue-Related Symptoms.

Background and Objectives: The current literature demonstrates that different cultures have different perceptions of the symptoms of Fibromyalgia Syndrome (FM). The aim of the study was to explore the differences between Brazilian and Portuguese patients with FM in their fatigue experience and to measure the differences in the perception of fatigue according to age and duration of diagnosis. Materials and Methods: In total, 209 Portuguese women aged between 21 and 75 years old (M = 47.44; SD = 10.73) and 429 Brazilian women aged between 18 and 77 years old (M = 46.51; SD = 9.24) were recruited to participate in the present study. Participants filled out the items in the Multidimensional Daily Fatigue-Fibromyalgia-17 Diary (MDF-Fibro-17), a specific tool to measure the level of five components of FM-related fatigue. Results: The results showed a greater perception of all of the components of fatigue in the Brazilian sample. No significant differences were found related to the age and duration of FM diagnosis. Conclusions: Overall, there are significant differences in fatigue symptoms between Portuguese and Brazilian women with FM, suggesting that cultural and geographical differences should be considered when describing fatigue-related symptoms in women with FM.