The association of fatigue, comorbidity burden, disease activity, disability and gross domestic product in patients with rheumatiod arthritis. Results from 34 countries participating in the Quest-RA programme

OBJECTIVES: The aim is to assess the prevalence of comorbidities and to further analyse to which degree fatigue can be explained by comorbidity burden, disease activity, disability and gross domestic product (GDP) in patients with rheumatoid arthritis (RA).METHODS: Nine thousands eight hundred seventy-four patients from 34 countries, 16 with high GDP (>24.000 US dollars [USD] per capita) and 18 low-GDP countries (6.6) compared with 23.0% in high-GDP countries (p<0.001). In univariate analysis, fatigue increased with increasing number of comorbidities, disease activity and disability in both high- and low-GDP countries. In multivariate analysis of all countries, these 3 variables explained 29.4% of the variability, whereas GDP was not significant.CONCLUSIONS: Fatigue is a widespread problem associated with high comorbidity burden, disease activity and disability regardless of GDP