Comparison of seronegative and seropositive rheumatoid arthritis with regard to some clinical characteristics

The aim of this study is to establish a scientific comparative analysis between seronegative and seropositive rheumatoid arthritis (RA), with regard to some clinical characteristics. The studied group consisted of RA seronegative patients with titters lower then 1:64 defined by Rose-Waaler test, while the control group consisted of RA seropositive patients with titters of 1:64 or higher. Examinees all belonged to the 2nd and 3rd functional classes according to ARA criteria, were between 25-60 years of age (Xb = 49.96), with disease duration between 1-27 years (Xbox = 6.41). In the disease onset most frequently affected joints were metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joint of the hands, almost equally represented with regard to sero-status and sex. During the examination seropositive patients showed a higher presence of inflamation of peripheral joints of hand and foot, but only the presence of PIP of the hands was statistically significant (chi2 = 15.63, p < 0.01). Knees, talocrural joints and elbows were more frequently affected in seropositive patients, whereas humeroscapular, coxofemoral and sacroiliacal joints were more frequently affected in seronegative patients, but without significant statistical difference with regard to sero-status. The presence of affected PIP of the hands (chi2 = 9.96, p < 0.01) and knees (chi2 = 4.17, p < 0.05) with regard to sex was statistically significant in seropositive female patients, as well as the presence of atacked PIP of the hands (chi2 = 6.08, p < 0.05), and cervical vertebrae (chi2 = 6.00, p < 0.05) in seropositive male patients. There were some differences between groups with regard to sex in metatarsophalangealjoints (MTP), PIP of the foot, and other joints, but without any statistical significance. In both subsets statistically significant domination was found in affected second (chi2 = 20.85, p < 0.01) and third (chi2 = 15.70, p < 0.01) fingers of the PIP level of hands and third finger (chi2 = 6.52, p < 0.05) of the MCP level. The mentioned parameters did not show a significant statistical difference with regard to sero-status and sex. Majority of patients had 1-4 deformities. Seropositive group had prevalent knee contractures, e.g. the eversion of the foot, while seronegative group had more "swan neck" deformities. The mentioned parameters did not show a significant statistical difference with regard to sero-status and sex. Longer duration of the disease resulted in an increased number of deformities, and this difference was statistically significant (t = 5.92, p < 0.01). Linear correlation between these two parameters resulted as high positive in general (r = 0.49, p < 0.01) and for groups separately, but without significant statistical difference with regard to sero-status. Duration of the disease with regard to the type of deformities was different in both subsets: in case of the longer duration of the disease "buttonhole" was prevalent with statistically significant difference in seropositive patients (t = 2.10, p < 0.05), whereas "fibular deviation" was prevalent in seronegative patients (t = 2.64, p < 0.01).