Rheumatoid arthritis in Senegal: a comparison between patients coming from rural and urban areas, in an urban tertiary health care center in Senegal.

Several studies have suggested that rheumatoid arthritis (RA) is uncommon in rural sub-Saharan Africa. The aim of this study is to determine the potential differences between patients with RA living in rural areas and those living in urban areas. We performed a cross-sectional study from June 2006 to May 2009. We included all patients with RA (1987 ACR criteria) seen at the Rheumatology Unit of the Le Dantec Teaching Hospital, Dakar, Senegal. We compared the main socio-demographic and clinical characteristics of patients living in rural areas to those living in urban areas. We included 180 patients in our study, of whom, 143 (79.4 %) lived in urban areas and 37 (20.6 %) in rural areas. The median age was 44 years [range 34-55] in patients from rural areas vs. 41 years [range 30-53] in patients from urban areas, without any statistical significance (p = 0.24). Patients under the age of 60 mostly lived in urban areas (p = 0.03). The extra-articular manifestations were significantly more frequent in patients living in rural areas (p = 0.02). There was no statistical significance when comparing the delay in diagnosis, number of swollen joints, disease activity, hand deformities, and concentration of autoantibodies (RF and ACPA) in both populations. The percentage of patients seen from the rural areas of Senegal is low (20.6 %) compared to those seen from the urban areas. The number of extra-articular manifestations is the main difference between patients living in rural and urban areas. The role played by environmental factors seems important. Further incidence studies are needed.