Periodontitis and Porphyromonas gingivalis in Patients with Rheumatoid Arthritis.

Purpose: To examine the degree to which shared risk factors explain the relationship of periodontitis (PD) with rheumatoid arthritis (RA) and to examine associations of PD and Porphyomonas gingivalis (Pg) with disease features. Methods: RA cases (N=287) and controls (N=330) underwent a standardized periodontal examination. HLA-DRB1 status was imputed using SNPs from the extended MHC. Circulating anti-Pg antibody was measured using ELISA and subgingival plaque was assessed for the presence of Pg using PCR. Associations of PD with RA were examined using multivariable regression. Results: PD was more common in RA (35%, p = 0.022) and aCCP positive RA (n=240; 37%; p = 0.006) vs. controls (26%). There were no RA-control differences in anti-Pg or the frequency of Pg positivity by PCR. Anti-Pg antibody showed weak but statistically significant associations with both anti-CCP (r=0.14, p=0.022) and RF (r=0.19, p=0.001). PD was associated with increased swollen joint counts (p=0.004), DAS-28-CRP (p=0.045), total Sharp scores (p=0.015), aCCP (p=0.011), and RF (p<0.001). Select anti-citrullinated peptide antibody (ACPA; including antibody to citrullinated filaggrin) were higher in patients with subgingival Pg and higher anti-Pg antibody levels irrespective of smoking. Associations of PD with established seropositive RA were independent of all covariates examined including evidence of Pg infection. Conclusions: Both PD and Pg appear to shape RA-related autoreactivity in RA. In addition, PD demonstrates an independent relationship with established seropositive RA. © 2013 American College of Rheumatology.