Rheumatoid arthritis (RA) is biologically marked by a positive serum rate of rheumatoid factor (RA) and/or anti-citrullinated protein antibodies (ACPA). Nevertheless, 20% of RA cases remain seronegative.
The main purpose of this study, is to bring out the clinical, biological, imaging, therapeutic, and evolutionary distinctions between seropositive RA and seronegative one.
This is an observational cross-sectional study that involves patients with RA admitted in the rheumatology department, from the period between January 2012 and January 2018. RA seronegativity is described as the absence of both RF and ACPA, while seropositivity is recognized by the presence of at least one of the two antibodies.
294 patients were included, of which 90% were seropositive and 10% seronegative. Therefore, RA in this study is seropositive most often. The bivariate analysis underscored plenty of differences, statistically notable, according to the RA immune status. In fact, patients with seropositive RA had more synovitis (p=0.049), more deformities (p=0.01), and more bone destruction on radiographs (p=0.04). Furthermore, RA in this Moroccan study was quite severe (p=0.006) and got more complicated by systemic manifestations (p=0.02). Whereas, no distinction was brought up between the two groups, concerning the use of biotherapy. As for the multivariate study, seropositive RA in these patients, had greater severity (p=0.009, OR=4.53) and was more deforming (p=0.03 OR=2.45).
RA in our Moroccan context is dominated by the seropositive form. This seropositivity is often coupled with clinical severity and joint destruction, resulting in more deformities.