Disease Activity Index and its Association with Serum Concentration of Anti-cyclic Citrullinated Peptide 1 (Anti-CCP1) in Patients with Rheumatoid Arthritis

Rheumatoid arthritis (RA) is one of the most frequent autoimmune diseases in the world which affects about 1% of the worldwide population. Measurement of the Anti-CCP1 titer in these patients is one of the new tests that is available in our country. It has been shown to be more specific than Rheumatoid Factor (RF) in the diagnosis of RA (97%) in multiple studies. This test becomes positive in early disease and it has a high predictive value. Patients with high levels of this antibody (positive) have more radiological erosions and destruction in their joints as compared to the negative patients.Some researches show that the level of this antibody has moderate correlation with disease activity. The aim of our study was to determine the relationship between Anti-CCP1 and disease activity in patients with rheumatoid arthritis. A cross-sectional study was performed on 90 patients with RA for evaluating the relation between Anti-CCP1 titer and disease activity index. Patients were selected by simple sampling method. Blood specimens were taken for detection of Anti-CCP1 titer and ESR. DAS28 form was completed for each patient. Data was analyzed with SPSS V.15 software. Statistical analysis performed with t test and Person's correlation coefficient. There was moderate correlation between disease activity index and Anti-CCP1 titer (p<0.001, r=0.57). The largest linear correlation was between Anti-CCP1and VAS; it means that higher titer of Anti-CCP1 is associated with more painful joints in our patients. The average of disease activity index in our positive and negative Anti-CCP1 patients was 5.07±1.1 and 3.5±1.5 (p<0.05), respectively. Because there was moderate correlation between Anti-CCP1 titer and disease activity index (r=0.57), this test cant be used as a marker of disease activity in rheumatoid arthritis patients.